This is cool.
It's a site one of my students hooked me up with -- you send people books you don't want, and get credits for doing so, and then you can get people to send you books you do want, for free, basically. (You do have to pay the postage to send books out.)
When you sign on and post nine books, you get three free credits up front.
I've been messing with it for a few weeks now, and it works just like it says it does. The kid has gotten two free books by Allan Ahlberg that we've always wanted and never been able to find, I got a mythology text I wanted to look at for my summer I class (which I probably could have gotten free from the publisher, but didn't have the patience to try that), also a mystery novel I've been wanting to read for awhile, I'm waiting on another book I wanted to read -- it's all good!
If you're as book-starved as we always are, or a poor student, you might have a look.
3 hours ago