The Money Behind the Comparison
If you have ever wondered how a price-comparison site manages to list hundreds of retailers, maintain a team of writers and developers, and still offer its service completely free to you, the answer is straightforward: affiliate commissions. When you click a link on a comparison site and go on to buy something from, say, John Lewis, Currys, or Very, the retailer pays the comparison site a small fee. That fee is typically a fixed amount per sale or a percentage of the order value, and it is the primary way these businesses keep the lights on.
There is nothing hidden or sinister about this arrangement. It has been the backbone of online publishing since the late 1990s. Understanding how it works, however, helps you use comparison sites more intelligently and spot the rare cases where the model is being abused.
How Affiliate Commissions Actually Work
When a retailer joins an affiliate network — common UK networks include Awin, Rakuten Advertising, and Commission Junction — it sets a commission rate for any sales generated by partner publishers. A comparison site signs up as a publisher, embeds tracked links into its pages, and earns a commission every time a reader clicks through and completes a purchase.
The mechanics look like this:
- You search for, say, a particular coffee machine on a comparison site.
- The site displays prices from multiple retailers, each price linked with a unique tracking code.
- You click through to a retailer and buy the product.
- The affiliate network records the sale and attributes it to the comparison site.
- The retailer pays the commission — commonly anywhere from 1% to 10% of the sale value, depending on the product category.
Commission rates vary considerably. Electronics typically carry lower rates because margins are thin; fashion and home goods tend to carry higher ones. Some retailers offer flat fees per sale rather than percentages. Crucially, the price you pay as a consumer does not change because of the commission — the retailer funds the fee from its own margin.
Why This Does Not Make Comparison Sites Untrustworthy
The instinctive worry is that a site will promote whichever retailer pays the highest commission rather than the one offering the genuinely best deal. This concern is legitimate but, in practice, easier to guard against than you might think.
First, a comparison site’s core value proposition is accuracy. If readers consistently find that clicking through leads to a worse deal than the headline price suggested, they stop using the site. Reputation is a meaningful commercial incentive to stay honest.
Second, UK regulation provides a legal floor. The Competition and Markets Authority (CMA) has made clear that price-comparison services operating in the UK must not present rankings in a way that misleads consumers about what drives their order. The Advertising Standards Authority (ASA) enforces similar standards on paid promotions, requiring that any sponsored or promoted listing is clearly labelled. Hiding a paid placement inside what appears to be an organic ranking is a breach of the UK Code of Non-broadcast Advertising (the CAP Code).
Third, many comparison sites deliberately separate their editorial rankings — sorted by price, rating, or relevance — from paid promotional slots that retailers have specifically paid to appear in. This is the same basic model as a Google search results page, and it is legitimate provided the distinction is visible to the reader.
What UK Law Requires Sites to Disclose
UK consumer protection law, shaped by both the CMA’s guidance and the ASA’s enforcement of the CAP Code, sets out clear expectations:
- Sponsored or promoted listings must be labelled as such. Terms like “Sponsored”, “Ad”, or “Promoted” are acceptable; vague language is not.
- Ranking methodology must not be actively misrepresented. A site cannot claim to rank purely by price if commission rates are secretly influencing the order.
- Affiliate relationships should be disclosed clearly. Many reputable sites include a short statement along the lines of: “We may earn a commission if you buy through links on this page. This does not affect the price you pay.”
- Price accuracy matters. Displaying a price that is no longer available, without a reasonable attempt to keep data current, can be misleading under the Consumer Protection from Unfair Trading Regulations 2008.
If you cannot find any disclosure on a comparison site — no affiliate statement, no explanation of how results are ranked — that is worth noting. Legitimate sites have nothing to gain from hiding it.
How to Spot Ranking Manipulation
Even with regulation in place, not every site operates to the same standard. Here are practical ways to sense-check what you are reading:
- Sort the results yourself. Most reputable comparison tools let you re-sort by price low-to-high. If the default ranking looks very different from the price-sorted view, check whether the top results are labelled as sponsored.
- Cross-reference with a second site. If a retailer appears at the top of every list on one comparison site but rarely features on others, probe why. It may simply be a strong retailer — or it may reflect a commercial arrangement.
- Check delivery costs and conditions. A headline price of £49.99 with £6.99 delivery from a lesser-known retailer may look better than £54.99 with free next-day delivery from a major retailer. Good comparison sites surface total cost; weaker ones do not.
- Look at the retailer’s independent reviews. Trustpilot, Google Reviews, and Reevoo provide signals about whether a retailer is reliable, which a price comparison alone cannot tell you.
- Read the site’s “About” or “How We Make Money” page. Reputable comparison sites publish this. The absence of any such page is a yellow flag.
A quick reference for what good disclosure looks like versus what to be cautious about:
| What good practice looks like | What to be cautious about |
|---|---|
| Sponsored listings clearly labelled | No labelling on any listings at all |
| Affiliate disclosure statement present | No mention of how the site earns money |
| Price-sorted view available to users | No way to change the default ranking |
| Total price including delivery shown | Delivery cost hidden until click-through |
| Ranking methodology explained | Vague claims of “best” with no criteria |
Getting the Most From Comparison Sites
Used with a degree of awareness, affiliate-funded comparison sites are genuinely useful tools. They aggregate information that would take you a long time to gather manually, and the commercial model that funds them does not automatically corrupt their results. The key is to treat them as a starting point rather than a final authority.
- Use the filtering and sorting tools to see results on your own terms, not just the default view.
- Factor in the full cost of purchase: delivery charges, minimum spend thresholds, and returns policies all affect the real value of a deal.
- If you are buying a high-value item — a laptop at £900, a washing machine at £600 — spend a few minutes verifying the price on the retailer’s own site directly, since data on comparison sites can occasionally lag behind real-time pricing.
- Treat sponsored placements the same way you would treat a shop window display: the product in it may be perfectly good, but it is there because someone paid for the position, not because an editor independently judged it the best option.
The affiliate model has funded a great deal of genuinely helpful consumer journalism and tooling in the UK over the past two decades. The sites that do it well are transparent about the arrangement, maintain editorial standards that serve the reader first, and comply with CMA and ASA requirements. The sites that do it badly are, frankly, not hard to identify once you know what signals to look for.
The key takeaway is simple: an affiliate commission does not make a comparison site dishonest, but it does mean you should take thirty seconds to check whether results are clearly labelled, whether the ranking methodology is explained, and whether the total price — not just the headline figure — is what you are actually comparing. Do that, and price-comparison sites remain one of the most practical tools available to UK shoppers.