Book Swap club
I am a devout audio book lover. There is a great site named paperbackswap.com. There is no membership cost; you simply list your books (paperback, hardback, CD, MP3, or cassette) by ISBN (the 10 or 13 digit number on the back of your item). You simply agree to mail your requested item to another member. You get credit in return - a book gets 1 credit; audio stuff gets 2. You use your credits to request books from other members. The cost of postage is minimal because lots of things can be mailed at media rate. For example, I usually mail a 5-6 disk audio book for $2.41.
To pay for postage, I buy paperback bucks from the club. That way, I have money in the system that I can draw on to either print my label with postage paid or I can affix my own stamps. A few cents got to support the club costs but I don't mind b/c I get so much for my money. Often books cost $15 to $30 depending on the media. With your credits, you can get a member to mail you a book. All it costs is some of your credits. You get credit for your trade that you can use to get what you want from another member.
Give it a shot. You will be happy you did. But be warned, it is addictive! I now have lots of books just waiting to be traded with other members.
My club name is audiolady. Have fun looking.