I’m a professor. I really try not to have expensive textbooks in my classes. The bookstores flat out refuse to stock older editions when there’s a new, expensive edition. Some refuse to stock textbooks that are cheaper, period. Every single semester, I get textbook sales reps that come bother me during my office hours to try to get me to use their textbook. I even had one come into my class and stop me in the MIDDLE OF MY LECTURE. It sucks, but we can also be sued for copyright infringement if we distribute free PDF’s of a textbook. And it’s looked down upon to only use articles and not have any textbooks in your classes. I know people make fun of professors who do this, but sometimes this is why professors make cheaper textbooks themselves and have students buy their own book. So they can have some control over pricing. The students see a textbook that costs $60 that their professor wrote, and he/she thinks that the professor is trying to make money off the student. But the truth is, other textbooks with the same material might be $150.