Paperback Swap & Amazon Paperback Swap is an online trading site. Registration is free, but if someone orders a book you’ve listed, you must pay the shipping. On the flip side, you can use the credits you earn to order “free” books from other members.
Opening an Amazon account and selling your used books can help to bring in a little extra spending money, or you can sell back certain copies of books in exchange for an Amazon gift card. Check out Amazon.com for more details.