I'm guessing some of you already know about PaperBackSwap but I had no idea this even existed until my cousin emailed me to tell me she requested a book for me. For those not in the know, you can list books that you have that you want to get rid of and people can request them from you. You just mail it to them and then you get a credit to order a book from someone else. Right now there are over 4.4 million books listed! I wish I had known about it sooner because I donated lots of books to Goodwill earlier this year. You get 2 free credits if you list 10 books so I already requested a book and someone already requested one of mine so I'll get another credit when she receives it. Genius!
Re: PaperBackSwap
Cool! My friend swears by Bookmooch, which sounds very similar.
I get my books off the donation shelf at the library. Can't beat $1 each... but it can be hit or miss. =D