If you have a Kindle, or even the Kindle app for your computer (or like in my case, my iPhone) then you'll want to know about this website. Reviews and free books are posted here (not just for the Kindle either). If you subscribe to the feed you'll get all the info delivered to your inbox.
There's usually a couple of good Christian fiction novels. Today the offerings are books by Kathy Herman and Erynn Mangum.
There's always discussion about the value of authors offering their books for free. Personally, I like it because it gives me a chance to try out books and authors I might not otherwise get around to. Like any kind of marketing promotion, it's bringing the authors' names to my attention. And that's not a bad thing.
A good example is Elizabeth White. I'd read a sample chapter of one of her books awhile back but never got around to getting the book. When two of her books became available for free on the Kindle, I got them and devoured them. She's now one of my favorite writers, and I'm going to pick up anything by her that I can. So in this case I'd say offering a free book has definitely paid off.
So get a free book and maybe find a new favorite author.