You can list the books you've finished reading and/or don't want anymore, and you can pick books that you want to read. It works on a credit system, but all you pay is postage to mail the requested books to other members.
When I first joined I didn't do too much with the site. I don't read a lot of paperbacks because I find the print too stinkin' small. Annoying. So I figured really, what good would it do me? Then I listed some books we had used for homeschooling when Zach was in 2nd. Those books flew off my shelves and I had these credits I wasn't sure what to do with.
So, I started looking - and there are not just paperbacks listed. Some people have hardcover and audiobooks listed too. I've found a couple of books that are first or second in a series I'm reading, hardback, and requested them. The postage I paid to mail out those other books is way less than a book would cost.
I'm using paperback swap for my hard to find books. The ones I can't get from any branch of our library. If you've come into a series late, it's a great idea!
Anyway, check it out. The button below will take you to the site. If you use me planetcaddick as a referral I'll get one credit, but no money is involved in any way. Just my piece of honest blogging.

~ Anyone who says they have only one life to live must not know how to read a book. ~ Author Unknown