Free ebooks

I think I wrote already that I received a Kindle Fire. I'm loving it and just today paid for my first book. I was given a gift certificate for amazon.com, so I figured I might as well use it. I bought "Unlocked" based on a good recommendation. I've still yet to read it. BUT what I wanted to say. Maybe some know or maybe others are figuring things out, but I checked on Christianbook.com and searched free ebooks and it showed some! I can't figure out if I can download from there, but I searched those titles on amazon and most were there for free! I just love seeing the priced crossed out and replaced with a $0.00!