* Online retailers: There are many online retailers that sell books at a discount, such as Amazon, Book Depository, and Thriftbooks. You can often find free shipping offers or discounts on multiple books.
* Library book sales: Many libraries hold book sales throughout the year, where you can find gently used books for a few dollars each.
* Book exchanges: Book exchanges are a great way to trade your old books for new ones. You can find book exchanges online or at local libraries and bookstores.
* Subscription services: There are a number of subscription services that offer discounted books, such as Book of the Month Club and Amazon Kindle Unlimited.
* Buy in bulk: If you're looking to buy a lot of books, you may be able to get a discount by buying in bulk from a wholesaler or publisher.