Library Dust’s post “Books on the Cheap” points out that the straightforward menu offered by publishers is often not the best way to get books at reasonable rates:

As a patron, I’m not at all unhappy with paying tax money to fund a library. Given that, I like to see the money used well; in my book that means finding cheaper sources for materials so that there’s money available for other things—like salaries. I like my librarians well-paid; they act better at the reference desk and I don’t have to fear that one of them is going to take a bite out of me to supplement her bag lunch. Just for fun, see how cheaply you can get selections from the bestseller list, especially in comparison to your current method.