A.:
I also use The Grocery Game. Like others said, you may end up buying things you don't want or need if you're not careful and disciplined. But at the same time, I've tried things I wouldn't have otherwise. I always get a kick out of seeing if I can beat my running total (about $47 savings in coupons) each time.
The lady on the GMA show is Kathy Spencer. Her website is a Yahoo Group called How to Shop for Free. She also has a Big Tent version that's better and has a $1 (yes, one dollar) annual fee to join. The fee keeps out the spammers rather well. She is the one who purchased $267 worth of groceries for $0.05 total. It's all through doubling and matching sale items to coupons.
In San Antonio, with HEB being our major, if not only, grocery chain, you won't find the same type of deals as they do not double or triple coupons. But like someone else said, HEB is already lower without doing so.
Even without the ability to double coupons, I've learned a lot from following TheGroceryGame.com (once you're past the free period it's about $1.25 a week - which you make up in savings easily) and from what I read on the HTSFF pages and daily emails. If you have the time to sit and work the system, you can save big.
There's no quick fix to get there and there's no magic wand. You have to spend time clipping coupons, organizing and comparing sales but it is possible to make a very significant dent in your grocery budget with a little bit of effort.
Good luck!