Half.com is great for clearing out your college text books. I had my share lying around, fifteen years of working on a degree will do that to a Chic.
(my half.com site)
Amazon is amazing for selling Antique, Vintage, and Out of Print Books. Let me say that again, Amazon is Amazing!
http://www.amazon.com/gp/shops/storefront/index.html?ie=UTF8&marketplaceID=ATVPDKIKX0DER&sellerID=A2LGIQSZ7F1F5R(my amazon store)
Today I sold this book on Amazon...
(Babes in Toy Land)
Yes that's right, Babes In Toy Land and why not? Some kiddos have not read it yet. This is the order information I received from Amazon.
Item: Babes in Toyland by Bluth, TobyCondition: New
Condition note: perfect. suitable for gift giving
Order date: 03/26/2012
Buyer's price: $19.99
So how did I come about this book? Not from my personal collection of rare books. I actually bought this at auction. Sometimes I randomly bid on book lots because nobody else in the auction house is putting their hand up. Its not unusual for me to buy six books for $1-$3 this way. Sometimes the books are winners, like this one turned out to be. This is one of those books people remember from childhood and they want to read to their own kids. Bless their hearts.
So there you have it, "Sell books its worth it!"