Another site that is similar to the grocery game is Coupon mom. It's free she just asks that you usse some of the coupons in conjunction with the sales to donate items to local food pantries.
They do the research, so you don't have to clip the coupons all at once, instead you leave the intact, then you chose your local store and she tells you what the proce is after the sale and coupon, and you clip only the ones that you want.
I really like it, give it a try - there's no charge. (no I don't work for them, I just really like the concept, especially combining it with donations to the food pantry)
Trying again, October '06 goal : a consistent size 18/20