Many textbooks are published for a specific state or university. The best place to sell these used textbooks for free is on your campus. Post notes on school bulletin boards with your first name, phone number, the books you are selling, and the prices. You may be able to charge up to 75 percent of the original price depending on the condition of the books.
If you have a Facebook or other social network account, advertise on your personal page. Post individual pictures with descriptions, prices, and the titles of the courses that require the books. Consider the cost of shipping when pricing the textbooks in case potential buyers live out of town.
In college towns, there are usually bookstores that specialize in buying textbooks. They are often located near the campus. Ask upperclassmen about these stores; they have probably already discovered the stores and can give you directions.
Any online search engine will provide website information for selling textbooks for free. Read the home pages carefully. Some sellers take your books, sell them on consignment, and extract a fee. Look for those that buy your books up front. Also, search for sites that send prepaid postage labels to save money on shipping. Before mailing books, do some research about the site to make sure it is legitimate. Look for customer feedback or complaints.