Textbook publishers are now putting homework, video, and audio content online for students as a supplement to their textbooks.
Some students at the University of Arizona are having to pay nearly 100 dollars per class for an access code to do homework and quizzes.
The cost of the codes can be included in the cost of the textbook only if the physical book is new.
These codes can cost from 30 to 150 dollars on top of what a student pays for the physical book.
U of A senior Hannah Cassidy says she's figured out how to save over the years by purchasing used textbooks but that doesn't get her out of buying a new access code, those can only be used once.
"There have been classes where I could just buy the access code and I could figure it out on my own or sometimes they would post the original documentation online, and then you'd have to buy the access code. But for one of the classes in particular that was most frustrating the online test that you need access to came directly from the book itself," Cassidy told KGUN9.
The textbook codes are being the called "the future of the textbook industry" and many are being used in place of a textbook.
U of A astronomy professor Thomas Fleming says he understands why the textbook companies charge for these codes because they've been losing money when students buy used books from the bookstore or from third party sellers.
"I'm torn because we want to see the students get their education without going bankrupt," Fleming told KGUN9.
The access codes expire after a certain amount of time, students say its frustrating that they cannot have the material forever if they needed it for multiple classes.