The course packs were either all original material, or an original composition of parts of case studies, essays, and text books; they were almost always under $50 (except in the case where licensing the copied portions drove the cost higher).
If a professor is actually just teaching out of a standard text book, all the relevant information is taught in lecture. If there is an express need for a textbook, it's on reserve at the school library.
I would urge every student to only consider purchasing a textbook if they really think they need it two weeks into class. Textbooks are overpriced, only a small amount of the information is relevant to the class, and the information is often redundant and can be found in lectures/slides. (if the idea of coming to class without a book is scary, check your school book store's policy on returning books)
The alternative to buying a copy of texts you really need (and I know there are a lot of legal issues with this) is "finding" the book online (and I haven't yet had a book I couldn't find trivially). A couple of PDF's instead of a pile of dead trees, and I have the added advantage of in-text search.