## Why books are the classic starter flip
Books are where most resellers start, and for good reason. Charity shops sell them for 50p to £1, they are everywhere, they are easy to post, and the right ones sell on eBay for £5 to £20. The stock costs so little that a bad buy loses you a pound, not fifty.
The catch is that most books are worth nothing. The shelves are dominated by mass market fiction that eBay is already drowning in, and the valuable titles sit hidden among them looking exactly the same. You cannot tell a £15 book from a 50p book by looking at the cover.
That is the whole case for a book scanner app. Instead of guessing, you scan the barcode on the back, see what that exact edition sells for on eBay, and only buy the ones with real money in them.
What an eBay book scanner app actually does
Every book published since around 1970 carries an ISBN, the International Standard Book Number, and on modern books it is printed as a barcode on the back cover. That barcode identifies the exact title and edition, which makes books the easiest category of all to research. There is no ambiguity about which product you are holding.
A book scanner app reads that barcode with your phone camera and looks up the live eBay market for it. With ScanJunki's eBay barcode scanner you see the prices the book is listed at, how many other sellers have it, and what you would keep after eBay fees and postage. ISBNs are supported alongside ordinary EAN and UPC product barcodes, so the same scanner works on the book shelf and the rest of the shop.
The decision then takes about three seconds. Sells for £12 with few competitors, buy it. Sells for £1.50 with two hundred listings, back on the shelf.
Where to find the ISBN on a book
- Back cover, bottom corner: the barcode on almost every modern paperback and hardback. This is the one to scan.
- Copyright page: the ISBN is printed inside the front, usually on the page after the title page. Useful when a price sticker covers the barcode; you can type the number in instead.
- Two numbers on the back: some books carry a second, smaller barcode for the retail price. Scan the main one, which starts 978 or 979.
- Older books: books from before the mid 1980s may have a ten digit ISBN and no barcode, and very old books have no ISBN at all. Those need a manual title search, which is slower but occasionally where the rarest finds hide.
One practical note for charity shops: price stickers love to sit directly on the barcode. Peel gently or use the copyright page number rather than damaging the cover.
Which books to buy and which to skip
Patterns emerge quickly once you scan a few hundred books. Broadly:
Worth scanning
- Niche non-fiction: specialist hobbies, trades, military history, railways, crafts, obscure biographies. Small print runs and dedicated buyers keep prices up
- Textbooks and technical books: current editions of university and professional texts hold value, and students buy used
- Manuals and reference: workshop manuals, vintage computing, photography guides
- Signed and first editions: check the copyright page, not just the barcode price
- Recent hardbacks in good condition: some hold value in the window before the paperback lands
Usually skip
- Mass market fiction: airport thrillers, celebrity autobiographies, last decade's bestsellers. Millions were printed and eBay reflects that
- Book club editions: cheaper printings that collectors avoid
- Old textbook editions: a superseded edition can be worthless while the current one sells for £30
- Anything with water damage or a broken spine, whatever the title
These are tendencies, not rules, which is exactly why you scan rather than memorise. Every seller has a story about the unremarkable looking book that turned out to be worth £40.
Grading condition honestly
Book buyers care about condition, and eBay's book conditions are specific. A rough guide:
- Like New: no visible wear, no inscriptions, could pass as unread
- Very Good: minor shelf wear, clean pages, no writing or highlighting
- Good: clearly used, may have an inscription or a creased spine, but complete and readable
- Acceptable: heavy wear, writing or highlighting, but intact
Always check inside before buying. Highlighting through a textbook or a missing dust jacket on a hardback can halve the value. When you list, mention defects in plain words; honest grading is also what keeps returns and disputes off your account, which matters if you sell as a business. Speaking of which, once you are buying books specifically to resell, the eBay fees guide explains what a business seller pays and where the private seller line sits.
A realistic hour in a charity shop
It helps to go in with sensible expectations, because book scanning is a volume game.
- Scanning takes a few seconds per book once you find a rhythm, so an hour covers a few hundred books if the shelf is accessible
- Most books you scan will be worth nothing. Hit rates vary hugely by shop; the interesting question is not the percentage but whether the hour produced a handful of £5 to £20 books
- Shops that price everything at 50p to £1 leave room for profit on modest titles. Shops that look up prices themselves leave less
- Non-fiction shelves are usually worth more of your time than fiction shelves, for the reasons above
A reasonable session might turn up five to ten sellable books. At charity shop prices that is a few pounds of stock that can return several times what you paid, and unlike most categories, the downside on any single mistake is about a pound.
This is eBay arbitrage in its lowest risk form, which is why books remain the standard advice for a first sourcing trip.
Try it on your own shelf first
You do not need to wait for a charity shop run to see how this works. ScanJunki is completely free, so sign up and scan the books on your own shelf tonight. You will learn the rhythm of scanning, see real eBay numbers for books you already own, and you might discover the first thing you list is something you already had.