There is one first-time-free paleo book:

Some of you are going to like this one:

The Ketogenic Diet: A Blood Sugar Solution by Dr. Robert Short
http://www.amazon.com/dp/B00B2EGVXI

There are also two others that were also free in the past. See:
http://www.amazon.com/s/rh=n:283155,k:paleo,p_n_feature_browse-bin:618073011&sort=price