There are two first-time free paleo books:

This is the last in its series to go free.

The Paleo Snacks For The Working Woman Easy And Delicious Paleo 
Recipes Volume 1 by Jessica Andrew
http://www.amazon.com/dp/B00A46DOE4

Paleo Lifestyle Magazine Interviews - Issue #1 - August 2012 by Paleo 
Lifestyle Magazine
http://www.amazon.com/dp/B0093U6U98

These were also free in the past:

Paleo Diet Solution: Lose Weight The Easy And Healthy Way With Fat 
Burning Foods Paleo Diet Guide With Recipes And Meal Plans by Sofia D'Andrea
http://www.amazon.com/dp/B009BAT3LM

The Paleo Aficionado Dessert Recipe Cookbook (The Paleo Diet Meal 
Recipe Cookbooks) by Amanda Matthews
http://www.amazon.com/dp/B009AIN6V8