Ecommerce marketing channels: what a sale costs in each

There are eight main ecommerce marketing channels, and they fall into three groups: those you pay for with time (SEO and content, email and organic social), those you pay for per view or per click (Google Ads and Shopping, social ads on Meta and TikTok, price comparison sites and influencers on a fixed fee), and those you pay for per sale (affiliates and creators). That difference matters most for your bottom line. Your contribution margin decides which channel suits you: it sets how much a sale may cost before it becomes a loss.

This guide shows how to work out your cost per sale by channel with your own numbers – not with industry averages that rarely fit your store. Affiliates are one of the eight channels, and there we use Affilyflow as the example, because we can show exactly how the price is calculated. The amounts are in Danish kroner (DKK), the currency Affilyflow settles in today, but the formulas work in any currency. If affiliate marketing is new to you, start with the guide to affiliate marketing.

The channels are listed in the order they are covered further down – it is not a ranking. The best channel is the one where a sale costs less than the contribution it brings you.

All eight channels require that you can measure a sale. Without measurement, the budget ends up with the channel that reports the most sales – not the one that creates them. Think about who owns the customer relationship afterwards, too: your email list and your SEO traffic are yours, while reach on social media, in Google and through an affiliate is borrowed.

Some lists add retargeting, marketplaces and SMS. They are not separate channels here: retargeting is a way of using the ad channels on people who have already visited, a marketplace is a place where you sell and pay a fee on each sale, and SMS works like email with stricter consent and a price on every message.

Every paid channel takes payment somewhere in the chain from view to sale. The earlier you pay, the more of the risk you carry yourself: a view that never becomes a click, and a click that never becomes a purchase, are paid for anyway. Pay per view (CPM) is typical for social ads and banners. Pay per click (CPC) is how search ads, Shopping and many price comparison sites charge. Pay per sale (CPS) is how affiliates and creators on commission are paid.

SEO, email and organic social are paid for with time and tools, and the bill is the same whether ten sales come in or a thousand. That makes them cheap per sale when they work – and expensive when they don't.

Paying per sale is not automatically cheapest. The price per sale can easily be higher than in a good click campaign. The advantage is that a sale never costs more than you decided, and rejected sales cost nothing. The drawback is that you cannot buy volume – partners have to choose to sell your products.

You need four numbers from your own store. They are in your shop's reports and in your ad account – not in an industry survey: your average order excluding VAT and shipping (AOV), your contribution margin, your conversion rate from click ads and your cost per click in the ad account. The contribution margin is the share of the order excluding VAT and shipping that is left once cost of goods, payment fees and the part of shipping the customer doesn't pay for are deducted.

1. 01

   Contribution per order

   Order × contribution margin. That is the amount a sale gives you for marketing and profit.

2. 02

   Cost per sale in click ads

   Cost per click ÷ conversion rate. At DKK 3 per click and 2 % conversion, a sale costs DKK 150.

3. 03

   Your ROAS

   Order × conversion rate ÷ cost per click – the same as revenue ÷ ad spend.

4. 04

   Break-even ROAS

   1 ÷ contribution margin. If your ROAS is below it, you lose money on every sale.

5. 05

   The price as a share of the order

   Cost per sale ÷ order. That is the total price per sale that would cost you the same as the click ads if you paid per sale instead.

At 2 % conversion, the store makes DKK 90 per sale after marketing. If conversion drops to 1 % – because the campaign reaches a broader audience, or because it is low season – the same click costs twice as much per sale, and every sale loses DKK 60. That is the risk of paying for clicks: the cost per sale follows the conversion rate, and you only know it afterwards.

When you pay per sale, the price is fixed. A total price of 25 % at Affilyflow means that a DKK 600 sale costs DKK 150 excluding VAT – DKK 120 to the affiliate and DKK 30 in network fee – however many clicks came before it. A Danish store pays 25 % VAT on top. The catch is that your conversion rate decides whether affiliates keep sending traffic. You work out the cost per click with the formula above. The price when you pay per sale you can try here with your own order:

Break-even ROAS is the ROAS at which marketing eats the whole contribution: 1 divided by the contribution margin. If 40 % of an order is left, every DKK 1 spent on ads has to bring in DKK 2.50 in revenue excluding VAT before the channel breaks even. Everything above that is contribution towards salaries, rent and profit.

At break-even, a sale costs exactly your contribution. That is the ceiling for what a sale may cost – not the target. The same conversion works for a fixed price per sale: the equivalent ROAS is 1 divided by the price as a share of the order.

The split is Affilyflow's: the network fee is 20 % of your total price, and the affiliate gets the other 80 %. Always compare excluding VAT on both sides. Danish stores pay 25 % VAT on top of commission and fee, and it is also drawn from the balance – see payments and balance. An EU store with a VAT number verified in VIES is invoiced with reverse charge, and a store outside the EU pays no Danish VAT. This is general information, not tax advice.

A good ROAS is above your break-even ROAS, with room for what is not in the calculation: salaries, software, returns and customer service. There is no number that is good for everyone. A ROAS of 4 is a fine result with a 50 % contribution margin and a loss with a 20 % margin. Also check what the number is calculated on. A ROAS looks better than it is when:

• revenue includes VAT. With 25 % Danish VAT, a ROAS of 5.0 is only 4.0 excluding VAT – and the same goes for any sales tax that is counted in.
• returns are not deducted. A product that comes back brought in no revenue, even though the ad still counts it.
• the campaign mostly reaches people who already knew you – searches for your own name and past customers. Many of them would have bought anyway (incrementality).
• the platform also counts purchases after a view without a click, or counts a sale that another channel counts too.

If you are asking what the average cost per click is in your industry, the honest answer is that we don't publish averages – and an average doesn't tell you what your own keywords cost. Google Ads has a keyword planning tool that shows a price range for the keywords you want to bid on. Once a campaign has run for a while, your own cost per click is in the account. Put that number into the formula above.

Here are the eight channels with what they require and when they make sense. The order is not a ranking.

1. SEO and content

SEO is paid for with time: a fast shop, category pages that answer what the customer searches for, product pages with real descriptions and guides to the questions customers ask before they buy. Coverage in the media and on other sites gives you links, which also help your SEO. The channel is slow to build, but the traffic is yours, and an extra visit costs nothing extra. Measure organic visits and sales per page, and give it months rather than weeks before you judge it.

2. Google Ads and Shopping

Search and Shopping ads catch customers who are already looking for the product. You pay per click, the price is set in an auction, and Shopping requires a product feed in Google Merchant Center – and both require that you track purchases. The channel gives you data fastest, because you can start and stop the same day. Keep searches for your own brand name separate from the rest – they convert well, but many of those customers would have found you anyway. Remarketing shows ads to people who have visited the shop. It converts well too, but many of them were on their way back anyway, so measure it separately. Set a ceiling for the cost per sale before you start, not after the first invoice.

3. Meta, TikTok and other social ads

Social ads create demand among people who weren't looking for you. You usually pay per view, even when the campaign is set to find buyers. It takes ad creative that works without sound and in a few seconds, and a pixel that only sets cookies once the visitor has said yes. With the pixel you can also retarget people who have visited the shop and given consent – measure that separately, for the same reason as remarketing in Google. Measure cost per new customer rather than the platform's own ROAS, and move the money to what sells – not to what gets the most likes.

4. Email and newsletters

Email is the channel where you own the recipients. The automated flows do most of the work: a welcome to new subscribers, a reminder about an abandoned cart and an email after the purchase. As a rule you need consent to send newsletters – in Denmark under the Marketing Practices Act, and the rest of the EU has similar rules – so signing up must be an active choice. A new online store has few recipients, so the gain lies in building the list from day one.

5. Price comparison sites

Price comparison sites show the same product at several stores, sorted by price. The traffic is ready to buy, but competition happens on price, so work out what it does to your contribution margin. Some sites charge per click, others per sale. The channel requires a product feed with correct prices, stock and preferably EAN or GTIN numbers. If you already have a Google Shopping feed, the same feed can be used at Affilyflow, so affiliates can search your products and link straight to them (products and feed).

6. Affiliates and creators: pay per approved sale

Affiliates are sites, newsletters and creators who recommend your products with a trackable link and earn commission when someone buys. At Affilyflow you set a total price per sale – usually as a percentage of the products excluding VAT and shipping (the exact base depends on the platform, see payments), or as a fixed amount. The amount is drawn from a prepaid balance.

A sale is approved automatically once the approval period has passed – 30, 45, 60 or 90 days, so it can follow your return period – unless you have rejected it or it is marked for review. If a whole order is refunded, the sale is rejected automatically with the WooCommerce plugin and Stripe, and a partial refund lowers the commission in proportion. On the other platforms you reject the sale yourself within the period, and a rejected sale costs nothing. Read more about sale approval.

The channel's weakness is pace. Affiliates choose for themselves who they sell for, and they compare your rate, your cookie window and your conversion rate with other programs. Set rules for coupon sites and paid search from the start. We measure ad clicks and referrals from coupon sites on the click – we can't see the search term – and once the rule guard enforces the rules, a clear breach earns no commission. Creators can also get a personal discount code that earns them commission without a click, but personal codes don't work through the Shopify app. Know the signs of affiliate fraud, and build the program with the affiliate marketing strategy guide and the guide to choosing affiliates.

7. Influencers on a fixed fee

An influencer on a fixed fee sells you content and reach. You pay the same however many people buy, so the deal is closer to a view channel than a sales channel – in return you get content you can often reuse, if the agreement says so. Give each influencer their own link or a personal code, and remember clear ad disclosure (in Denmark, the Consumer Ombudsman's rules; elsewhere, the local equivalent). A middle way is a lower fee plus commission on sales. More in the guide to influencer marketing.

8. Organic social and communities

Posts on your own profile and in groups cost only time, but the reach is borrowed: the platform decides how many of your followers see the post. The channel is best for showing who is behind the shop. Use UTM parameters on your links so the sale can be traced back to the post – otherwise the traffic ends up in your statistics as direct visits.

The choice depends on your contribution margin, your budget and your time. The margin comes first: with a low margin, break-even ROAS is high, and click ads then have to convert unusually well to make money.

How much should an online store spend on marketing?

There is no percentage that fits everyone. The ceiling is your contribution per new customer: if you spend more on winning a customer than the customer gives you, you lose money on growth. If customers buy again, you can pay more for the first order – but base it on what a customer is really worth over time (LTV), and compare with what a new customer costs in each channel (CAC). Start with a budget you can afford to lose while you learn.

The cheapest way to lower the cost per sale in every click channel is to get more of your current visitors to buy. Cost per sale is cost per click divided by conversion rate, so if conversion goes from 1 % to 2 %, the cost per sale halves without the cost per click moving.

• Conversion (CRO): fast pages, good product photos, shipping and delivery made clear before checkout, and reviews close to the button.
• Order value: accessories on the product page and a free-shipping threshold a little above your average order. A bigger order gives more contribution per paid click.
• Repeat purchases: the post-purchase email and reminders about products that run out. Every repeat purchase without a new ad lowers the real cost of having won the customer.

This also applies when you pay per sale. Your price per sale doesn't change, but affiliates' earnings per click (EPC) rise when your shop converts better – and that is one of the numbers affiliates compare programs on.

Compare the channels on the same number: contribution after marketing – the order's contribution minus what the channel cost for the sale. Some call it profit on ad spend. ROAS and the number of sales are useful metrics within each channel, but they don't tell you whether the channel makes money for you. Keep the rules the same:

• Same tax treatment: all revenue and all costs excluding VAT or sales tax.
• Same period – and revenue after returns.
• New customers counted separately: a channel that mostly reaches regular customers creates fewer new sales than its number says.
• Same source of truth: your own orders in the shop, not the sum of the platforms' reports.

A blended number is a useful check. Total revenue divided by total marketing spend – sometimes called MER – cannot count the same order twice, because it starts from your own revenue. It just doesn't tell you which channel did the work. That is what the per-channel numbers are for. In the same way, keep the cost per sale in a campaign (CPA) apart from the cost of a new customer across everything you spend (CAC).

UTM parameters tell your analytics tool which source a visit came from. An affiliate network uses a click ID in the link to tie the sale to the affiliate who should get the commission. At Affilyflow, the commission and the cookie window are locked on the click, and the same order cannot count twice in a program. Use both: UTM to compare channels and the click ID to settle. How a sale is tracked from click to approval is explained in affiliate tracking.

The plan is for a new or small online store that wants to get going without spreading itself across every channel at once. Take one week at a time, and only move on when the previous week's task works.

1. 01

   Week 1: Measurement and margin

   Go through the checklist above, and make sure the cookie banner works, so the shop can track purchases with consent.

2. 02

   Week 2: One click channel

   Start Shopping or search ads on the products you sell most of, with a daily budget you can afford to lose and a ceiling for the cost per sale.

3. 03

   Week 3: Email flows

   Set up a welcome email, an abandoned-cart reminder and a post-purchase email, and collect sign-ups with consent on the homepage and at checkout.

4. 04

   Week 4: A program where you pay per sale

   Create a store account, set a total price from your calculation and an approval period that follows your return period. Install tracking, make a free test purchase with the test link, and share your invitation link once the program is visible.

If your shop runs on Shopify, tracking is done with the Affilyflow app in the Shopify App Store without code in the theme – the details are in affiliate marketing for Shopify stores. WooCommerce has its own plugin, and the other platforms each have a guide – start with getting started as a store or see all integrations.

After 30 days you have numbers from one channel you pay per click, one you pay with time and one you pay per sale. Give the affiliate program more than a month – partners first have to find and choose you, and the full plan for the program is in the affiliate marketing strategy guide. Then put the next money where a sale costs least compared with what it brings in. Price and terms for a program are on start an affiliate program.

Written by

Alexander Matthiessen

Co-founder, sales and customer relations

Makes sure Affilyflow’s partnerships grow – and that the platform delivers what both businesses and affiliates have been promised.

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