Ask your bookstore about the process for ordering additional books in case one you need sells out. To protect your opportunity to return unneeded textbooks, find out your store's refund policy before your buy books. It is usually posted near the cash registers. Depending on your store's return policy, shop early to find used books. If you decide you don't need a used book you've bought, please return it as soon as possible to give your fellow students a chance to save money.
Packages can be a great value, but do some research before buying one.
A used textbook may be a better value if all the components of a new set aren't really necessary for success in the class. Virtually all stores require receipts for refunds. Return materials you don't need as soon as possible so they can be re-sold to someone who needs them. Don't write in new books until you're sure you will keep them. Acquiring your own library of textbooks can provide significant benefits, especially those in your major or in a subject matter you intend to pursue further in college or career.