Cashback services return a portion of the affiliate commission they earn on your purchase. The mechanism is legitimate and the failures are predictable.
How it works
The portal holds affiliate relationships with retailers.
You click through the portal to the retailer, which sets a tracking cookie identifying the referral.
You purchase, the retailer reports the sale, the network pays the portal a commission, and the portal passes a share to you.
Which means the money comes from the retailer's marketing budget rather than being added to your price, and the portal's margin is the difference between the commission received and the cashback promised.
The tracking failures
Which cause most of the missing claims.
Ad blockers and privacy settings preventing the tracking cookie from being set, which is increasingly common as browsers restrict third-party cookies.
Clicking another link between the portal and checkout, which under last-click attribution reassigns the commission.
Using a coupon code from elsewhere, which on some retailer programmes overrides the referral entirely.
Completing the purchase in a different browser or on a different device from the one that clicked through.
And taking too long, since tracking windows expire.
The excluded categories
Where claims fail for reasons that were disclosed and not read.
Retailer terms commonly exclude gift card purchases, items bought with gift cards, certain brands, sale items, and anything where a competing discount was applied.
Marketplace purchases from third-party sellers are frequently excluded even where the platform itself is a partner.
And subscriptions and renewals are generally excluded after the first purchase.
These are listed on the retailer's page within the portal and almost nobody reads them, which is where the frustration comes from.
The payment delay
A structural feature rather than a stalling tactic.
Cashback is generally held until the retailer confirms the sale and the return period has passed, which for many retailers is months.
The portal cannot pay before it has been paid, and the network cannot pay before the retailer confirms.
Which means delays of several months are normal and are not evidence of anything wrong.
What is worth watching is whether the transaction was tracked at all, which appears within days, since an untracked purchase will never resolve on its own.
The rate variability
Worth knowing because it affects timing.
Rates change frequently and portals compete on them, running elevated rates during promotional periods.
Comparison sites exist showing rates across portals for the same retailer, which is worth checking for anything substantial.
The difference between the best and worst rate for the same purchase can be meaningful, and the effort is a minute.
The stacking question
What can be combined and what cannot.
Cashback frequently stacks with a retailer's own promotional code, and frequently does not stack with codes from other affiliates.
It generally stacks with credit card rewards, since those operate on a different mechanism entirely.
The reliable approach is to use the portal link last, apply only codes from the retailer or the portal itself, and complete the purchase in the same session.
Whether it is worth the effort
An honest assessment.
For large purchases, the amounts are meaningful and the extra thirty seconds is clearly worthwhile.
For small purchases, the tracking failure rate and the delay make the expected value modest.
The behavioural risk is real. Cashback creates a reason to buy, and a percentage returned on something unnecessary is a loss regardless.
Which is the same caution that applies to every mechanism in this category, and it is the one that costs people most.
What to do when it does not track
Portals have a missing claim process, requiring the order number and date, generally within a stated window.
Success rates on these are moderate and depend on whether the retailer can find any evidence of the referral.
Which means recording the click and the order reference at the time, for anything substantial, is the preparation that makes a claim possible.
Bank and card-linked offers
An alternative mechanism worth knowing about.
Many banks and card issuers offer cashback linked directly to the card, activated in an app, with no click-through required.
Because attribution is by transaction rather than by cookie, the tracking failures described above do not apply, which makes them considerably more reliable.
Rates are generally lower and the offers are narrower, and the certainty is worth something.
These stack with portal cashback in some cases and not others, and checking the terms is worthwhile for anything substantial.
Timing and rate changes
A practical detail that affects the amount received.
The rate that applies is generally the one displayed at the moment of click-through, not the one displayed when the sale confirms.
Which means a screenshot at the time of clicking is useful evidence if the credited amount differs.
Elevated rates during promotional periods are genuine and short, and portals frequently announce them in advance, which is worth watching for anything planned.