Grocery Challenge- Can it be done?

I recently stumbled across this blog and really enjoy it! She recently published two books that I would very much like to get, and is issuing a grocery challenge for September. She is aiming to feed her family of 10 on $75 a week! I am aiming for the same amount for my family of 6, as we're in a higher cost of living area. But, I am also including a buffer of $100 for eating out and such in the budget, as John and I are going to go on a date this month, and I'd like to have the little bit of wiggle room. So far, I have spent approx. $100 for the month, going over my weekly goal because of the siren call of a farm stand ( : So that leaves 50 dollars for next week. Seeing as we really just need a few things like milk, kids toothpaste, etc., we should be fine! I am interested to see if I can really do this by applying myself to paying more attention to shopping the freezer and pantry, better planning, and less impulse purchases. Wish me luck! And feel free to join the fun- check out owlhaven.net. I'll update as the spirit moves me ( ;