Sometimes I feel like I'm beating a dead horse when I talk about this, but not that many people I know use it, so it must not be dead enough: Interlibrary loan is incredible.
Just now, I saw a Susan Sontag quote
that seemed contemporary, then saw that it was from a book published in 1977. Then, I headed to the Minuteman Library Network
, searched for it, and hit the "Request It" button.
Now, it will be shipped to a library close to me. I'll get an email about it in couple days, then I'll walk over, take it home, and read it (or not). All for free.