How RedGem works out profit, line by line

Most reselling tools hand you a profit figure and expect you to trust it. We think you should be able to check ours. Every deal on RedGem ships with its full working, line by line, and this page is the method behind that working. If a number on the site ever disagrees with what you read here, tell us and we'll fix one of them.

The short version: we start from what an item actually sells for on eBay, judge how likely this particular product is to sell, count every cost between the auction hammer and your bank, and only then call what's left profit.

Step 1: what it really sells for

Resale value comes from real eBay UK sold listings for the exact item, not asking prices and not the RRP. We take the recent sold range, trim the outliers, and use the middle as the typical resale, keeping the low and high ends so you can stress-test the flip.

Three guards keep this honest. If an estimate for a whole lot comes out above its RRP, the comparison almost certainly matched the wrong thing, so we cap it at RRP and mark our confidence down. If a valuation rests on a handful of live asking prices rather than completed sales, we apply a haircut, because sellers list aspirationally. And if the sold prices behind a match are suspiciously spread out, we flag it for a human check instead of pretending the average means something.

Step 2: the chance it actually sells

A Shark vacuum with hundreds of recent eBay sales is near-certain to sell. A niche gadget with thirty listings sitting unsold is not. Treating both the same would flatter the dud and undersell the winner, so every product gets its own sell-through rate, built from live evidence: how many have actually sold on eBay, how fast they're selling right now, and how many listings are competing.

Proven sellers earn a higher rate, which raises both the profit estimate and the safe max bid together. Products with measured slow demand get priced cautiously. Where we have no demand data yet, we fall back to an honest baseline based on the lot's condition, from around 98% for sealed stock down to 35% for spares and repairs. The rate we used, and why, is printed on every deal's workings.

Step 3: every cost between the hammer and your bank

• Auction fees. Each house has its own profile. At John Pye, for example, a 25% buyer's premium plus VAT means roughly 1.5 times your winning bid leaves your account. Houses with no premium are modelled at their real rates too.
• Getting the lot to you. Collection is counted as free; parcel delivery at the house's typical charge; genuinely oversized items at the oversized rate. Bulky lots are never costed like parcels.
• Selling costs. Private sellers currently pay no eBay final value fee, so we count £0 there, and we still deduct a postage and packaging budget per unit even though many buyers pay postage on top. Our numbers deliberately sit at the cautious end.
• Missing parts. If the listing or the photo suggests a missing charger, remote or cable, we price the replacement on eBay and subtract it before profit is counted.

Step 4: the safe max bid

The max bid is not a guess, it is the equation run backwards: the highest hammer price at which, after every cost above, you still keep roughly a 40% return on the money you put in. Bid below it and your margin grows. Bid above it and you're the one being flipped.

That built-in margin of safety is also why the headline profit can look conservative: it is the profit at your max bid, the floor of the plan, not the dream.

Why we show two numbers

Some people want to know the worst realistic case; others want to know the ceiling. So a deal shows both. Est. profit is the floor: win at the full max bid, sell at typical prices. Up to is the ceiling: the lot closes at today's bid and sells at the top of its recent range. Both come from the same maths with different inputs, and the workings for both are on the page.

What we will not do is quote the ceiling as if it were the promise. Out of everything on this page, that is the rule that matters most: attractive numbers are fine, invented ones are not.

Check it yourself

Every day one deal on the homepage is unlocked in full, workings and all, precisely so you can audit us before paying anything. Open the eBay sold listings link on the deal, compare, and make your own call. If our method holds up, the membership pays for itself with one flip.

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