I've bought a StoryBundle before - though I haven't had time to read any of the books from it yet. Their books come in 3 formats, DRM free.
From the email introducing the new Epic Fantasy bundle:
With StoryBundle, you can name your own price, pay what you think the batch of books is worth, and you'll get the first batch of six. If you pay $12 or more, you'll get three bonus books—Clockwork Angels by Kevin J. Anderson, The Immortals by Tracy Hickman, and The Emperor's Soul by Brandon Sanderson. – Kevin J. Anderson
The initial titles in the bundle (minimum $3 to purchase) are:
- The Sacrifice by Kristine Kathryn Rusch
- Spirit Walker by David Farland
- MythWorld by James A. Owen
- The Camelot Papers by Peter David
- The Monarch of the Glen by Neil Gaiman
- Bloodletting by Peter J. Wacks and Mark Ryan
Click the links to see what the books are about. And here's their website if you'd like more information or to buy the bundle.