The hardest part of reselling isn't finding stock. Charity shops, car boots and wholesale pallets are full of it. The hard part is knowing which of it will actually sell, and sell fast enough to be worth your time.
How to find stock that sells comes down to 3 questions you ask before you buy: will it sell, what will you actually make, and how much work is it going to take. Fail any one of the 3 and it's usually a pass, not a bargain.
Get this right consistently and sourcing stops being a gamble. Get it wrong and you end up with what experienced resellers call a death pile: stock you've bought but haven't listed, quietly eating your cash, your storage space and your motivation.
Most sourcing mistakes happen at the point of purchase, not later. If an item turns out to be hard to price, slow to list or unlikely to sell, that decision was made the moment you picked it up.
Every item you buy comes with a hidden bill: the time to handle it, photograph it, list it, store it and eventually post it. You're not paying that bill in money. You're paying it in hours. So the real question isn't "is this valuable?" It's "is this worth my time?"
Every potential purchase gets tested against the same 3 questions:
If an item fails one of those 3, I usually leave it behind. It's a simple filter, but it stops you buying on instinct alone.
There are 2 different checks here, and mixing them up leads to bad decisions.
For a quick check while you're sourcing: compare the number of recently sold comparable items with the number currently listed. If you see 70 comparable jackets sold recently and around 100 currently listed, that's roughly a 70% sold-to-active ratio. This is the rough, on-the-spot version most resellers use standing in a shop.
For deeper research: eBay's own Product research tool, found in Seller Hub, gives sellers up to 3 years of sales history for millions of items, including sold prices, sell-through rates and demand trends. It's free with Seller Hub access and also works from the mobile app, so you can look something up properly before committing to a bigger or less familiar purchase.
Vinted and Depop don't have an equivalent built-in tool. The workaround: search the item, and compare how many identical or near-identical listings are currently active against how many show as sold or have picked up recent likes. It's rougher than eBay's data, but a listing with steady recent sales tells you something. A listing that's sat unsold for months, even at a low price, tells you something too.
One more distinction worth making: compare like for like. A search against the exact brand, size and condition tells you far more than a broad category search. A 70% sell-through rate across "men's jackets" in general is close to meaningless. A 70% rate on the exact jacket, size and condition you're holding is a real signal.
Item A: £8 Nike sweatshirt. Sold comps at £25 to £30. Strong, consistent recent demand. 5 minutes prep. Easy postage. Buy.
Item B: £5 obscure vintage jacket. Listed online for as much as £70, but almost no actual sold comps. Needs washing. Bulky to post. Leave. The asking price looks exciting. The lack of proof anyone's actually paying it is the real story.
Item C: £40 Patagonia jacket. Sold comps at £80 to £100. High sell-through. Ready to photograph as-is. Postage is manageable. Buy, despite the lower percentage margin. A reliable, well-documented brand with genuine demand beats a higher-margin item you're hoping will sell.
[BILLY: your real bad-buy anecdote goes here, e.g. "I once bought X because it looked worth £Y. What actually happened was..."]
The lesson across all 3: cheap stock isn't automatically good stock, and a high asking price online isn't proof of a sale.
Say you've got £500 to spend on stock, and either buys you 50 items at £10 each. One version of that stock sells within 30 days. The other takes 12 months to clear.
Even if the eventual profit per item is identical, these are completely different businesses. The stock that sells in 30 days returns your £500 to you almost immediately, ready to be spent on the next round of sourcing. The slow-moving stock keeps that £500 locked up for a year, unable to work for you again in the meantime.
Your money needs to move, not just make a profit eventually. That's why sell-through speed matters as much as margin, and sometimes more.
You can't run full research on every item at a car boot sale or a rummage through a charity shop rail. Working out what to buy at car boot sales to resell usually comes down to a shortlist of quick checks instead of a full research session:
Some patterns should slow you down, without being an automatic no:
"When sourcing products, the costs and time to prepare an item for photography cannot be disregarded. It directly increases your time to list and decreases your profit per hour." — Myles Hunt, Hub Vintage
Sourcing is usually more fun than processing stock, and that's exactly why death piles happen. Buying feels like progress. But an unlisted item isn't productive inventory yet. It's cash you've converted into another job you still have to do.
A death pile grows when purchasing outruns listing: a few extra items at first, then a corner of a room, then a problem you stop looking at. My rule of thumb is not to buy more than 2 to 3 weeks worth of processing capacity at a time. If your death pile is already growing, that's the signal to slow sourcing and clear the backlog first, not to keep adding to it.
Sooner or later, something you bought won't sell at the price you hoped. Say you paid £30 for an item, priced it at £70, and 6 months later it's still sitting there. The market seems to be clearing closer to £40.
The £30 is gone either way. The decision in front of you isn't "I paid £30, so I can't sell for £40." It's "would I rather have this sat here, or £40 back in cash I can put into something that will actually sell?"
"The hardest thing to get over early on is the price you paid. You buy something for £5, list it at £20, it doesn't sell, and you'd rather it sit there than drop it. But that £5 is already gone whether it sells or not. Once I started thinking about it that way, sunk cost, done, move on, discounting became easy. I'd rather have £10 cash to reinvest than a £20 listing gathering dust." — Patrick Cooper, 3x Vintage Founder
There isn't one figure that's good for every item. Higher is generally better, but sell-through only makes sense alongside margin, purchase price and listing effort. A slower-moving £5 item with an £80 sold price can be a better buy than a fast-selling item that only makes £5 profit.
Neither platform has a built-in sell-through tool like eBay's Product research. Search the item, compare how many similar listings are currently active against how many show as sold or heavily liked recently, and treat a crowded, slow-moving search as a warning sign.
Buy roughly as much as you can realistically photograph, list and manage within 2 to 3 weeks. Buying beyond that builds a death pile of unlisted stock that ties up cash and space without generating any sales.
Neither on its own. A high-margin item that takes a year to sell ties up your cash and space just as badly as a low-margin item selling instantly wipes out your profit. Weigh both against how long the item will take to prep and list before deciding.
None of these checks take long once they're second nature. The 3 questions, the quick sell-through check, watching your death pile, it all becomes automatic within a few weeks of doing it deliberately. If you want the full system for running a profitable reselling operation, from sourcing through to pricing and dispatch, our Reseller Handbook 2026 covers it in more detail.