Feeding a family with nothing

I need some help here. I am getting ready to start a new series for everyone. I am going to buy groceries based on the sales each week to feed my family for the week on a minimum budget. This is not going to be for stockpiling purposes. If something ever happens with my husbands pay (such as we were told was going to happen a couple weeks ago with the government shut down) I want to know my family will eat. I know a lot of people are nervous about layoffs lately and the economy has not shown to much improvement. How do we prepare for that? We can build a stockpile but we can also learn how to handle an emergency situation in case you do not have a stockpile.I have a family of 7 although my husband is deployed so it will be for the 6 of us. There is my, my 14 year old, 10 year old, 4 year old, 3 year old and 1 year old. How long do you think this challenge should go on for before you would be a believer that you can feed a family on a very very low budget. What do you think is possible to do this with $30, $40, or $50 a week? I am hoping to get some responses to this. I value my readers opinions and want to give you something new to see and watch happen. Let me know your thoughts. Also don't forget to tell others about this page and go to the classes section if you want to set up a class.