Ever see those people leaving the campus bookstore looking discouraged, even a bit insulted? Well, they should be because they’ve been taken for fools and practically robbed blind.

According to a New York Times article, textbook publishers increase prices at an average rate of six percent each year, which is twice the rate of inflation. College bookstores sell new books at cost, but even used books are still pricey.

Let’s be honest, even with low enrollment fees, college is expensive. Students begin wondering how it is possible that they are spending more for textbooks than a full course load each semester–then they smarten up. A growing number of students now buy or rent their books online instead of purchasing them in campus bookstores.

Cheap textbooks can be found on sites like Half.com, CheapestTextbooks.com, and Amazon.com. Craigslist.com is a great site to find students from the same college willing to buy, sell or swap books. There are also local bookstores that buy and sell used textbooks.

Book rental sites like Chegg.com and Bookrenter.com are gaining rapid popularity at college campuses nationwide. Not only do they boast prices at a mere fraction of what used books cost at campus bookstores, but they also make the shipping and return process incredibly easy. Shipping is free at many of these sites and books typically arrive together in a box that can be saved for semester’s end, when it comes time to return the books with free postage.

These sites are becoming so popular because they also offer competitive rates for students looking to sell used textbooks. The average buyback price on Chegg.com is $40. Try getting that back at the end of the semester, if the campus bookstore is even accepting them.

College bookstores typically buy back books from students for 25 to 50 percent of the original price. If there are no new editions coming out, the same used books are marked up and resold, then bought back again for much less. Publishers send campus bookstores the latest edition of many textbooks every few years, making older editions obsolete for campus bookstores, though just as useful for students. Rental sites buy back older editions of textbooks, and older editions can also be rented for less.

Many of these websites are even involved with charities. Collegebookrenter.com has given over $15,000 to the American Heart Association. Chegg.com plants a tree for every book rented, bought or sold. Greentextbooks.com recycles old books and donates a minimum of five percent of each purchase to the Arbor Day Foundation and the World Wildlife Fund. And Bookrenter.com has already raised $25,000 in funding for relief efforts in Haiti.