I discovered paperback book swap last year and think it's the best invention since movable type. My original idea was that using pbs would be a way to attain book stasis in my house--for every book purchased, one would be posted on the site and the number of books crowding my shelves would not increase. It was a good idea and it's mostly worked. The problem is that whenever I log on to the site to post new books or to claim a credit for a book I've sent someone else, the welcome page automatically throws up a selection of books I might be interested in.
I am always interested in these books. Old books by authors I know, new books by authors I've never heard of, translations of foreign thrillers...the list is pretty long. So long in fact that I now have 23 books on my "wish" list (one of which hasn't been posted since 2005) and 1525 on my "reminder" list. I have one available credit. Somehow the math does NOT add up.
I highly recommend pbs for anyone who wants to trade books. You get several free credits just for signing up. Yes, you have to pay postage on the books you ship out, but it's almost always less than you'd pay for a used book unless you buy all your books from yard sales. Most of the books I've gotten are in pristine condition--even re-giftable. They also have hardbacks.
They also have the review and social networking features you get on Good Reads. Some of my friends swear by Book Mooch, which is optimized for several different languages.
Right now there are four books on their way to me and five I've sent on their way. I have that one credit. And thousands and thousands of books I can "spend" it on. I feel rich.