Make a list of your collection. Jot down all relevant information, including each book's title, author, publication date, publisher and edition. Also write down each book's condition (fine or like new, very good, good, fair or poor) and whether it is a mass market or trade paperback. Mass markets are smaller paperbacks, the kind sold on racks at drug and grocery stores. Trade paperbacks are larger, generally 5 ½ by 8 inches or 6 by 9 inches, but sizes vary. Entering your information in a spreadsheet program will help you keep better track of it.
Research each title on used and out-of-print retail book websites such as abebooks.com, alibris.com, powells.com and amazon.com to get rough estimates of their worth. Write down each book's approximate value and the minimum dollar amount you're willing to accept for it.
Contact bookstores that specialize in used and out-of-print paperbacks. These businesses usually have specific hours when they examine books for purchase, but you might have to make an appointment. In general, bookstores offer cash or store credit for books they buy from the public.
List your books on eBay. Post them in one category, such as Antiquarian & Collectible Books or cross-post in several sections, such as General Fiction, General Nonfiction, and Paper Collectibles. If you list your books in lots of 10 or 20 rather than individually, you may be able to sell them more quickly. In each listing, include a clear photograph of the book and any important information, including the book's condition, whether it's signed by the author and any relevant edition information. You also can post books for sale with eBay's subsidiary company, half.com, but you can list each book only on one site at a time.
Sell your books on Craigslist, which has a specific classified category for books. Before you list your books, decide whether you want to include your phone number or just your email address in the ad. Craigslist also provides you the option of securing an anonymous email address. In your ad, include all the information you would include in an eBay ad. Photos are optional but may help attract buyers.
Sell your books at a garage sale if you're unable to sell them by any other means. This should be your last resort, as yard-sale shoppers typically are thrifty and are used to paying minimal sums for paperback books.