Freebook sifter great for free Kindle books
I have been using this new site for finding free Kindle books, it's updated daily, and broken down into categories. Pretty plain site, no cover art, but when you select one it takes you right to the Amazon page. I use it as one more source along with pixel of ink, bookbub, bookgorilla, etc.
I just picked up one that sounded funny called Bubba and the Dead Woman.
Lots of options.
Here is a link that might be useful: Freebook sifter