"We required the students to buy the book"

This was always so odd to me. I used to think it was just a US weird thing but I understand it happens in many more countries as well (and maybe in my own country as well; I did go through my first degree literally two decades ago, and only at one university). When I went through my first degree, the lecturer provided the material - lectures and some handouts. Every so often there would be a reference to some book for some particular additional topic, but it was never required.