If you're an avid reader, you may really love paperbackswap.com. All you have to do is choose a book you'd like to read from a list and you'll receive it in the mail.

At the same time, you list the books you want to get rid of. When someone requests to read it, all you have to do is pop it in the mail. You will have to pay for postage, but it's usually around $2.13.