There are several online sources for renting textbooks that have excellent reputations. Some college bookstores have also jumped on the bandwagon to keep the revenues from textbook rentals.
One of the best sources, not surprisingly, is Amazon. Amazon has an entire section for college textbooks, including rentals, selling back old textbooks, and electronic textbooks for Kindle.
One of the advantages of using Amazon for your college textbook services is that it is Amazon, which is already a trusted source, and you can use any of your regular Amazon benefits like Prime Membership to further cut your book costs.
Another very highly regarded textbook rental company is Chegg. Chegg offers a good textbook rental program, as well as a textbook buy back program.
Companies that rent textbooks are cropping up, but be sure that you understand the rental terms before you agree to rent. The entire point of renting is to save money, so there is no reason to spend more when you rent.