I disagree with your last point. Don't think of it as paying $10/book for "something I'm only going to read once", because its more than that. Essentially you're paying someone to work hard and labor on a topic
you are interested in for years; and distill that years of research into a few hundred pages so that you don't have to do all the work.
Someone once told me that if you can get _1_ idea from a book that changes you're outlook on things; then it's worth it, and I agree. I don't understand how people can say $10 on a book is too much; you can friggin' spend more than that on one meal!
EDIT: And as eru said, if you still think its too much, join a library.