Anyone comparing cashback portals quickly notices a puzzle: one store offers a fraction of a percent while another offers several times more, and the same portal pays different rates for groceries, clothing, electronics, and travel. These differences are not random and they are not a mistake — they reflect how much profit each type of retailer makes on a sale, and how much of that profit they are willing to share to win your order. Understanding the logic behind the rates helps you judge whether a rate is good, and stops you chasing a high rate on a bad deal.

The basic mechanism is that a cashback portal earns a commission from the retailer for sending you there, and passes part of that commission to you. The retailer sets the commission based on its margin and on how badly it wants the sale. A business with thin margins cannot afford to give much away, while a business with fat margins or a strong need for new customers can afford to be generous. The rate you see is therefore a window into the retailer's economics, not a reward for your loyalty alone.

Grocery stores, fuel stations, and discount retailers typically offer the lowest cashback rates, because their margins are thin and their customers already shop there regularly — they do not need to pay much to attract an order. A grocery cashback rate that looks tiny can still be worthwhile, because grocery spending is frequent and the total adds up over a year, but it will never match the percentage offered by categories with more room to share. Fuel is similar: high turnover, low margin, and little incentive to discount through a portal.

Electronics sit in the middle. Margins vary by product — accessories and own-brand items carry more room than flagship devices sold at near-cost to attract footfall — so rates differ even within one store, and some products are excluded entirely. Always check whether the specific item you want is eligible before assuming the headline rate applies, and compare the final price across stores, because a store with no cashback but a lower price is still the better deal.

Travel, fashion, beauty, and subscription services typically offer the highest cashback rates, because their margins are larger and competition for each booking or order is intense. A hotel or flight booking carries enough margin that the retailer can share a meaningful percentage and still profit, which is why travel cashback often looks generous compared with groceries. Fashion works similarly, especially for new customers, where retailers pay a premium to win a first order in the hope of repeat business.

But high rates come with more exclusions and conditions. Travel cashback may exclude taxes and fees, which can be a large part of a booking, and may only pay after you have completed the trip, which can be months later. Fashion cashback may exclude sale items, gift cards, and certain brands, and new-customer rates may not apply if you have ordered from that store before. Read the category terms for the store, not just the headline rate, and calculate the expected return on the amount that actually qualifies.

Use category rates as a tiebreaker, not a decision-maker. When two stores offer the same item at the same price, the higher cashback rate wins, and over a year those tiebreakers add up. But when prices differ, the cheaper total price wins regardless of rate, because a generous percentage of an inflated price is still an inflated price. Keep a simple note of the typical rates for the categories you shop most, so you can spot an unusually good rate — a temporary promotion — and time a planned purchase to it without buying anything extra.

Finally, remember that rates change constantly as retailers adjust commissions, and a portal's rate today may differ next month. Check the rate at the moment you shop rather than relying on memory, and do not let a high rate persuade you into a category you would not otherwise buy from. Cashback is a discount on spending you already do; the moment it becomes a reason to spend, the retailer's margin logic has worked exactly as intended — against you.

Cashback rates differ by category because retailer margins differ: thin-margin groceries and fuel pay little, high-margin travel and fashion pay more, and exclusions decide what actually qualifies. Use rates as a tiebreaker on equal prices, check terms before you buy, and never let a generous rate create spending you did not plan.