There are five first-time-free paleo books:

19 Paleo Recipes For Your Family - Healthy Recipe Cookbook 
(Paleolithic Cookbook) by Victoria Sunsett
http://www.amazon.com/dp/B00C845HW2

The Paleo Cookbook (Breakfast Edition) - 30+ Days of Healthy and 
Delicious Paleo Recipes For the Whole Family!... by Ryan E. Taylor
http://www.amazon.com/dp/B00C69HBGO

Paleo Recipes For Quick Weight Loss. Secrets to lose weight fast the 
Paleo way. by Larry Haber
http://www.amazon.com/dp/B00CA7D2KQ

Paleo Recipes Meat & Fish - Paleolithic Cookbook of Healthy Recipes 
by Victoria Sunsett
http://www.amazon.com/dp/B00C8WWQDC

Paleo Beginners: The Complete Paleo Diet Guide With 30 Days Of Paleo 
Recipes by White Hot Kitchen, Lisa Stewart and Jeremy L.
http://www.amazon.com/dp/B00C4C8AQ8

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