When editions changed and problems were assigned from the books, most of the profs at my university would gladly provide copies of the updated questions. I even had a course where students would bring in photocopies of the prof's textbook to class, and he was still willing to pay a Knuth-esque stipend to students who found errors.

I had one that was the exact opposite, even going as far as violating the university policy by charging for quizzes. The administration refused to do anything about that one ...

I just went into the university bookstore & took photos of the question pages, lol. This was in the digital camera era, pre-smartphones, so it was hard to hide what I was doing and I got kicked out once or twice. Worth it to save hundreds of dollars.