I recommend Max Weiss's The Zen of Meeting Women over Gambler's stuff.
Gambler's stuff: $97
In my personal opinion, Gambler's stuff is weaksauce. I don't have this specific product, but I've read his newsletters and dabbled through his website, the private section of his website, and seen all the sarging videos from his crew. Nothing more than basics. I do highly encourage watching the videos at his website, though. You won't be impressed (American PUAs are way more awesome in-field IMO

), but it's always good to see the real shit.
The Zen of Meeting Women: approx. $20
One of this forum's members, Snubby (aka Zen) wrote this book. It combines eastern philosophy with pickup and offers a very clear an effective path toward becoming a real natural with this stuff. This has got to be one of the most "enlightening" texts I've ever read on pickup and I highly recommend it. You can find it here:
the-best-pua-book-ever-i-hope-so-vt10925.html