You can use the Internet to price and buy secondhand books. Book price matters if you are a collector or seller, or you simply want to save money. Compare prices of books you want by researching on the Internet. Websites such as alibris can inform you about book price and value; use BookFinder to compare prices before you buy. You can search by title, author or, as is often the best way, by ISBN number.
Find secondhand books at used bookstores. These stores often buy and sell books, so you can take your extra books to sell and receive a "trade" price that is often much higher than cash to use to shop for additional books. Some stores sell a wide variety of used books, while others specialize in distinctive categories such as military or cooking books. Used bookstores may have a high turnover rate, so do not expect a book to remain long on the shelves. Ask the staff to look for a specific book and request a notification if the book comes in to the shop.
Libraries and yard sales are other venues for finding secondhand books, but these sources are eclectic and unreliable if you are searching for a specific book. Many libraries sell books in less-than-stellar condition at an inexpensive price. Visit yard and garage sales in your area that advertise "books" in their ads to receive good deals. In addition, sellers at flea markets often sell books; visit on the last day of the sale since they often don't want to pack up large hardbound books and are anxious to sell.