These websites are some of my happiest discoveries. I've been using them for nearly a year now and, as a result, I have saved over $250 on books alone. I have gotten books from PaperBackSwap that are essentially brand new hardcovers. I recently received the newest Imogen Heap CD for just the $2 I spent sending a CD out to another member last year.
It's a pretty easy setup. Each of these websites work pretty much the same way; they're even linked so they're easy to manage, and you can transfer your credits back and forth too. All you do is sign up then add the books, CDs, or DVDs you want to get rid of onto the corresponding website. You add the item by typing in its ISBN number from the UPC code on back. When someone wants one of your books, CDs, or DVDs you just click that you agree to send it, print out their information and take it to the post office. You can even buy the postage directly through the site to save yourself that step. Then you put it in the mail. When they receive the item, they go into the system and mark that they got it, and you get a credit. You can use each credit to request a book, CD, or DVD from other members. Sometimes they're already listed online and sometimes you have to put it on your wishlist and wait because other members are waiting for it too. It's a great system. Plus, it gives you quite a bit of faith in the honesty of others because I have not had any bad experiences with this the whole time I've been doing it. You can even set up exceptions if you never want to get a book from a smoker or if you don't want to accept CDs without their liner notes. Love it!
The best part of this? I am consistently getting packages in the mail! Makes your day brighter to open your mailbox and discover a free book every time.