I found these Running Books for FREE or very INEXPENSIVE as an ebook on Amazon today:
1 - FREE - "Instant Running"
2 - FREE - "Running State"
3 - $0.99 - "Half-Marathon Roadmap"
3 - $1.27 - "Beginning Running"
3 - $1.99 - "The Long Run"
4 - $2.51 - "Runner's World Essential Guides: Weight Loss"
5 - $2.51 - "Runner's World Essential Guides: Fast Fuel"
6 - $2.51 - "Runner's World Essential Guides: Barefoot Running & Minimalism"
7 - $2.99 - "101 Simple Ways to be a Better Runner"
8 - $2.99 - "HIIT"
9 - $2.99 - "Crossfit Training Secrets"
10 - $2.99 - "101 Ways to Run Better Faster Longer"
11 - $2.99 - "Grandma Wears a Running Skirt"
12 - $3.95 - "The Duel"
13 - $3.99 - "My Own Medicine"
14 - $3.99 - "Smoothies for Runners"
15 - $3.99 - "Half-Marathon Running"
16 - $4.99 - "The Ultimate Beginners Running Guide"
17 - $4.99 - "Carved by God, Cursed by the Devil"
18 - $4.99 - "Marathon"
19 - $5.99 - "First Marathons"