If you're a reader, you know how expensive books, even paperbacks, can be. When 13year-old Rachel started her Language Arts class last year she brought home a reading list of over 200 books. That adds up to a bundle when you start purchasing them new. Of course the library is always an option but to find a book there when you need it is always a gamble. At about the same we started looking for books on the list, a friend told me about Paperback Swap. I guess Confucius was right: When the student's ready, the teacher will appear.
Paperback Swap is an amazingly well-organized web site (http://www.paperbackswap.com/ ) You simply list any books you don't need anymore. It's easy. You just input the ISBN numbers and then wait. When someone requests one of your books, you print out the label and ship it media rate (currently $2.19 for most paperbacks.) When your book's received, you get a credit. You can use your credit to request anything on the site (one credit for print books, 2 credits for books on tape and CD) There's even a wish list so you can ask for unlisted books and the site will notify you when they're listed. Your only expense is when you ship out books that have been requested from you.
I've used PBSwap to find all of Rachel's required reading, textbooks for her big sis Molly who's an English major at the University of Georgia, cookbooks and mysteries for me, audiobooks for listening on the long drive to grandma's house, even computer manuals for my techie husband.
When I'm browsing at thrift stores or yard sales, I always pick up paperbacks if they're priced under fifty cents and in good condition. Even if it's a topic that doesn't interest me, I list it on PBSwap- usually it's just what someone else needs.
It's been my experience that parenting books, histories (the more obscure and specific the better), cookbooks, health topics and religious/inspirational writings go in a hurry. Very popular authors such as James Patterson, Patricia Cornwell and Johanna Lindsey don't go quite as fast-there are usually lots of their volumes listed already.
An entire community has grown up around PBSwap- forums, chat rooms, recipe spots, games (20 questions, sudoku), maps so you can track where your books have come from and where the ones you sent out went. There's a place for writers to submit original work and for readers to critique it.
It's a great site that's run by a couple of kind souls from Duluth, GA. There's no charge to join or use the site and they're currently anticipating the listing of their 2,300,000th book.