NOTE: Be careful when buying textbooks from booksellers outside of the United States! Often these editions are different from those sold in this country, and may not be appropriate for your course. To avoid buying the wrong book, always check with your professor BEFORE purchasing a different edition.
In addition to the University Bookstore, there are a number of resources available for purchasing textbooks for your courses. Be sure that you're getting the right book by checking the title, author and edition/year before buying. If you have it, use the ISBN to locate the correct copy for a specific class. The ISBN is a 10 or 13-digit number that can usually be found on the barcode of a book. This number is unique to that title and is the quickest way of finding the book you need.
If you're not sure of the proper edition, contact your professor for more details.
Sometimes used textbooks will also be available at reduced prices. When possible, check the condition of the book before purchasing!
Here are some resources for finding used books online: