I still prefer print books over digital, but Ebooks are nice too. While you should definitely check out your local library for Ebooks, another source of free ones is BookBub. To use BookBub all you have to do is sign up. During the sign-up process you'll be asked about what genres of books you like, favourite authors, and favourite Ebook service (Kindle, Nook, Itunes, etc).
That's it. Sign-up and you'll receive daily email updates about free and reduced price Ebooks.
You can also check out this link daily to see what's available for free.