The title says it all. Sell your used books via BookScouter. Alternatively you could find some cheap books on thrift stores, flea markets, garages sales and sell these books via BookScouter.
Simply visit the site, enter the ISBN number of the book, and the System will automatically tell you how much your book is worth and which of the 40 sites pays the most.
If you spend enough hours you could make a ton of money.
Visit BookScouter: BookScouter.com