Many public libraries have a wonderful service called Interlibrary Loan or ILL. If your library doesn't have a particular title, they can borrow it for you from another library in their network. Besides books, patrons can request audio books, DVDs, magazines, etc. Librarians can also get items statewide and even nationwide. This is usually a free service to patrons, but some rural libraries charge for postage.
Definitely a service to check out with your local library!