There is one first-time-free paleo book:

25 Delicious Paleo Diet Recipes by Sarah Lyles
http://www.amazon.com/dp/B00CY0VIY6

There are also 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