My Mountain of Books traded for Someone elses Mountain of Books

Today I joined PaperBack Swap. I plan on trading My Mountain of Books that I have read for another Mountain of Books I want to read. It was so easy to join. I just went to http://www.paperbackswap.com/index.php signed up and listed 10 paperbacks I have already read. Instantly I received 2 credits. Which means I can order 2 books of my choosing. The sender pays the postage, so I get my two books for nothing. Now when someone orders one of my listed books I pay the postage to send the book to them and I receive a credit which means I can get another book. Easy as that. You get your books for the price of the postage. No hidden fees or gimmicks. This is great because I just started reading the Joanna Brady Mysteries by J.A. Jance and I can't seem to find them all at my library and I didn't really want to pay full retail for them.