The is a massive digital library seeking to provide universal access to all knowledge. Their Open Library project allows you to "check out" over 1.5 million e-books. It’s a fantastic resource for out-of-print books that you can't find anywhere else. How to Get These Books Onto Your Device

is a free newsletter that sends you daily alerts for $0.00 e-books based on your favorite genres.

Plug your device into your computer via USB and "drag and drop" the EPUB files into the device folder.

The Ultimate Guide to Finding Free E-Books for Your E-Reader

You don't need a massive budget to be a voracious reader. By using a mix of library apps, public domain archives, and daily deal newsletters, you can find enough free content to last a lifetime.