The price of Neanderthin goes up and down. A couple days ago several 
copies were available for just under $9, plus $3.99 for shipping. Now 
the lowest price is $12.75+.

I have installed the Camelizer addon for Firefox. It shows a graph of 
a product's price over time. I see that on last August 8th a 
paperback copy went for $0.18.

You can sign up for a price drop alert in Camelizer. See:

http://camelcamelcamel.com/NeanderThin-Caveman-Achieve-Strong-Healthy/product/0312243383

http://camelcamelcamel.com/NeanderThin-Caveman-Achieve-Strong-Healthy/product/0312975910

Click along the right to turn on 3rd Party Used.

The best deal IMO is for $18.99 + $3.99 you can get a new hardback 
edition. See: http://www.amazon.com/gp/offer-listing/0312243383/