One problem with books is, while often you can rent them or buy them used for a fraction of new, if the prof requires online access codes, you will have to buy them.
For example my D’s German book was $200 new but included the access code, a used one would have been cheaper, but the access code alone was $150, so I told her just to buy it new. Similarly with chemistry.
But she has been able to rent some of her books (bio, ochem) and saved money, some of her science and language books have been good for two semesters as well. It just depends.