There is one first-time free paleo book:

The Paleolithic Slow Cooker Cookbook by Jeremy L., Amy Atlas and 
White Hot Kitchen
http://www.amazon.com/dp/B00AFDWHO4

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