Cash, convenience, competitive prices and we will buy it no matter where you bought it. The CU Book Store will be buying textbooks Dec. 12-23 at the store in the UMC and locations throughout campus. Download our Free Sell Books Ap for iPhone or Android for an instant price quote. Search for "University of Colorado" in either app store. See website for hours, locations and sell back prices. You can also return your rental textbooks to any of our sell back locations.