Most people don't toss their used books, DVDs and CDs in the trash, but buying new consumes unnecessary resources (and a lot of cash), so why not trade your old ones for something that's new to you?
Swaptree.com is a cool website that allows you to keep a fresh, rotating selection of reading material, movies, and music for zero dollars. Who doesn't love free stuff? Just sign up, list your unwanted stuff, and choose the items you'd like to receive. Then, you simply complete the swap through the mail. Easy!