worse than that is professors being required by the school's contract with the textbook company to tell you to buy a book that they have no intent on using because it's awful. that was way way more common for me.
I loved getting my math degree. Almost every professor provided us with copies of the book. One went so far as to hand out flash drives with the pdfs on them on day 1. For the few classes I did buy books for, I went online and found the international edition, which was generally around 30 bucks instead of 300.
Fuck text book publishers and fuck school bookstores.
This! My English teacher in my first year required us to buy a specific book that she wrote from a specific book store for $250. You had to bring it and the receipt in proving you bought it and aren't just sharing with someone else.
We then opened the table of contents to "go over" the book and never touched it again.
She then said "you should probably leave those here so you don't forget them". Never fucking touched it again.
I had a hero of a physics professor who figured out that new editions of textbooks just mixed up the number of the exercises, so he advised students that they could just order previous versions of the textbooks and he'd provide the "key" for how the questions were shuffled.