Since the advent of the Internet, finding and purchasing used books has become an easy task. I can go online and, in minutes, find a used book at any one of a number of websites: ABE Books, Alibris, Powell's as well as e-Bay and Amazon.com.
Until fairly recently, with the exception of e-Bay, selling used books remained a local activity. Managing auctions on e-Bay for used books is usually too much effort for me. I have a local used bookstore to which I bring all my books (I now have a credit of more than $1,000 there).
Today I have two online resources to offer for the sale/disposal of used books: one for paperbacks and the other for hardbacks and textbooks.
www.paperbackswap.com: I first learned of this website almost exactly a year ago in an article in Publishers Lunch. Since that time, the Atlanta-based company has grown by leaps and bounds.
The concept is simple. You list the books you want to swap on the website. Once you have nine books listed, you earn three credits and can begin to swap for the books you want--one credit per book. When one of your books is selected by another member, you mail the book from your home to the new owner. Paperback Swap provides you with a mailer which you can print on your computer. They also provide the amount of postage you need to put on the package (based on the ISBN and usually about $1.59) and with the address to which you should mail the book. It couldn't be easier.
www.bluerectangle.com: The second site is mostly interested in hardback or textbooks in very good condition. You enter the ISBN numbers of the books you want to sell, and they immediately provide you with a cash quote of what they are willing to pay. They will even provide the postage (not just tell you the amount needed) via the mailer they send you over the computer.
While you're doing your spring cleaning, you might find a use for these two sites.