Got lots of books I finished reading (at least once) if anyone wants to come pick them up in brooklyn lemme know. I would love to get other books in exchange
Then paperbackswap should be good for you, you get new books for your old ones, the only price you have to pay is shipping on your old books, and the hassle of going to the post office every once in a while.
I use these guys a lot http://catalog.brooklynpubliclibrary.org/http://pac.theoceancountylibrary.org/polaris/
The brooklyn public library is now on line. You can rewew your books and even get an email a few days before they're due to remind you. It's saved me hundreds.