Profitable Charity-Shop Drift

Wander into charity shop (Cats Protection League, of course).
Find fabulous brocade jacket for £2.
Spend 20 mins scanning bookshelves for something to make this worthwhile.
Locate book, selling for 40p, which is on Amazon Marketplace for a minimum of £12.
Buy jacket and book okay, and another book. think of the kittenz!
List book on Amazon for £8.
Admire jacket, which has a net price in my head of -£5.60.