Jesse's book thread reminded me to post this.
Libby is a free app. You plug in your library card number and it allows you to borrow any electronic book that your library has access to.
You can read them through kindle app or on the Libby app.
You can also borrow audio books (my preference).
It allows you to place holds, see what's popular, etc.
I listen/ read 12+ books a year easily because of this app and driving back and forth to work.