Use this checklist at a charity shop, car boot sale or collection. Write down the identity, realistic selling price and full costs before agreeing a price. If a missing detail could erase your margin, resolve it first or walk away.
1. Identify the exact make, model and variant
Photograph the model plate, serial label, maker’s mark and included accessories. Check size, capacity, generation, colour and regional version: similar-looking items can sell for very different amounts. For clothing, record the tagged size and measurements; for electronics, confirm the actual model rather than trusting the box.
Use Check with Siggy as a starting point, then verify the identification yourself. An uncertain model is a reason to lower your maximum buy price, not to assume the most valuable variant.
2. Compare completed sales, not wishful asking prices
Search for the exact model and filter for sold items. Completed but unsold listings help show prices buyers rejected; they are not successful sales. Compare several recent UK sales with similar condition, accessories and delivery terms. Separate bundles, spares-only items and unusually high or low results.
Record the date, condition and total paid including delivery. A “best offer accepted” listing may hide the actual accepted price. If sold evidence is thin, use a conservative range rather than a single confident figure. SiggyFlip’s active eBay listings are asking-price evidence, not proof of sold value.
3. Inspect condition and completeness
Test the functions that matter: buttons, ports, charging, sound, moving parts and battery condition where safe. Look for corrosion, cracks, odours, water damage and previous repairs. Check every required cable, remote, lid, charger or fitting against the model’s requirements.
If you cannot test it, price it as untested rather than working. Get a realistic repair or replacement quote before buying; “probably a cheap fix” is not a budget. Photograph defects now so your later listing can describe them honestly.
4. Calculate what you will actually keep
Net proceeds before buying cost = expected sale receipts − marketplace/payment fees − postage and packing − repairs. Estimated profit = those net proceeds − purchase price. Include buyer-paid postage in receipts if you receive it, then deduct the actual delivery cost; do not count it twice.
Weigh and measure the packed parcel. Include packaging, collection travel and any paid promotion you intend to use. Check current fees for your seller status, category and marketplace; a calculator’s assumptions may not match your account. Keep tax obligations and the value of your time separate from this item-level estimate.
The eBay fees calculator gives a starting breakdown. Add repairs, packing and other costs it does not cover. Sell’s marketplace comparison can help compare options, but estimates are not guaranteed sale prices.
5. Set a maximum buy price before negotiating
Maximum buy price = conservative sale receipts − all selling costs − your target profit − a risk allowance. The allowance covers uncertainty such as returns or an accessory you have not verified. If the seller wants more than your ceiling, negotiate or leave it; do not raise your assumed resale price to make the deal fit.
Hypothetical example: a used music player
Assumptions only, not observed sales or current marketplace fee rates: sale receipts £60; total marketplace/payment fees £6; postage £5; packing £1; replacement cable £3; purchase price £20. No buyer-paid postage is added. Tax and your time are not included.
- Net proceeds before purchase
- £60 − £6 − £5 − £1 − £3 = £45
- Estimated profit at a £20 buy price
- £45 − £20 = £25
- Maximum buy price
- With a £15 target profit and £5 risk allowance: £45 − £15 − £5 = £25.
If the item only sells for £45 and other costs stay the same, profit at the £20 buy price falls to £10. Recalculate with your own evidence and costs; these estimates are not guarantees.
6. Check sell-through, time and storage
Count comparable sold items over a stated period and compare them with the number currently listed. Ten sales in 90 days against 200 active listings suggests more competition than ten sales against five. This is a rough signal, not a precise sell-through rate: stock changes, relisting and duplicate listings can distort it.
Consider seasonality, local collection demand and how long you can tie up cash or space. A bulky item with a good margin may still be a poor buy if it takes months to collect. Use Spotter to research candidates and Stock to track actual costs and time to sale.
7. Walk away from counterfeit or unsafe items
Do not sell something as genuine when you cannot establish authenticity. Logos, packaging and a serial number alone are not proof. Avoid recalled products, damaged lithium batteries, unsafe electrical goods and items with uncertain safety history such as child car seats or protective helmets.
Check applicable UK safety requirements and marketplace restrictions before buying. Selling regularly for profit may bring business-seller and tax responsibilities; keep records and check official guidance for your circumstances. Do not rely on an AI answer as a safety certificate.
Before you hand over the money
Can you name the exact item, show comparable sold evidence, explain its defects, price every cost and stay below your buy ceiling? If not, pause. A deal you leave behind costs less than stock you cannot safely or profitably sell.
Ask Siggy for help structuring your research, or return to Check with Siggy.