There are two first-time-free paleo books:

The 12 reviews for this first one are all purchased phony reviews 
(and should be voted down):

50 Healthy Slow Cooker Recipes: 50 Simple and Healthy Recipes for 
Slow Cooked Meals by Hanna Mason
http://www.amazon.com/dp/B00C015E9O

Paleo Diet Recipes: The 35 Most Effective Paleo Diet Recipes (How to 
actually use diets) by Jag Chohan, Stephen Robinson and UK Kindle Creations
http://www.amazon.com/dp/B00C67TJWK

There are also some 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