Willow Tree is a great place to find discount new and used books. There are thousands of used paperbacks in this quiet little store, with aisles organized by categories, such as Mystery and Suspense, Western, Romance, Kids, General Fiction and even Science Fiction, Fantasy and Horror. A Senior discount is offered to shoppers age 60 and older. Willow Tree will recycle your used books in exchange for store credit. ring along cash or your checkbook, though, because credit cards are not accepted.