My budget is $400 per month. I feed 9 people with this amount. We also frequently have parties or people over for dinner. My 6 kids range from 13 to 7 months. So obviously the 13yo would be eating much more than the 7 month old. Three adults are myself, DH, and my mother.
We eat breakfast, lunch, and dinner on this amount. We eat out at fast food about 3 times per month. But usually it is not all of us eating out. If one parent takes dd13 to a basketball tournament they will eat out lunch or whatever. Even fast food is at least $25 for that many people!
Breakfast is usually generic cereal, cinnamon toast, premade waffles (will only buy if they are $1/box) or already made foods. I will make a batch of pancakes or french toast and freeze them in a large ziploc so the kids can microwave in the morning. They are usually out of bed before me and make their own breakfast. If I am really lucky they are nice and get the little ones breakfast too! (I have great kids

)
School lunches are made the night before and once a kid is in third grade they have to make their own lunch. We fill reusable bottles with juice or koolaid. I usually have some sort of treat like brownies, cookies, jello, etc. to choose from. They take a sandwich, fruit, crackers,granola bar and a treat. They only get 15 minutes for lunch so they don't take much more than that. I don't buy any prepackaged items for lunches.
Dinners are some type of meat, starch, veggies, rolls. We make dinner every night and sit down as a family to eat it. Typical dinners like pot roast, roast chicken, tacos, etc.
When I go to the grocery store I have an idea of what the lowest price of an item should be and that helps me decide what to buy. I get the sale flyers first and make a list based on what's on sale. I try to have each day's menu planned out a week at a time based on sales and my schedule for the week. I also try to only go shopping once per week, because I can not go into a store for only one item, I come out with $35 worth of extras every time. In addition, my children are lactose intolerant so milk runs about $7/gallon.
I thought it might be helpful to list all of the items I don't buy rather than what I do buy:
Jello-snackpaks
individual bags of chips
premade rice crispys
individual yogurt cups
small ice cream containers (I buy the huge container and we add our own mixins - yummy! I eat ice cream every night it is my major downfall)
cake/brownie/bread mixes - I bake from scratch it doesn't take any longer and tastes better!
Juice boxes - fill reusable bottles it's cheaper and better enviromentally
Hamburger helper - rice a roni etc make from scratch
Pop - unless we are having a party.
Shredded cheese - buy in chunks and grate yourself in food processor
Crumbs - bread crumbs, cornflake crumbs, cookie crumbs - use a food processor
They get a lunch card in the beginning of the year with 10 lunches on it and that is it for the year. Hot lunch is $2.25 which is crazy!
One of my tricks is to bulk shop but hide some of the food. I have found if the kids see tons of food in the pantry they eat more than they otherwise would. If there are ten boxes of cereal in the pantry they would open all ten boxes and some would end up getting stale. Same goes for chips.
I am a SAHM so my time is more flexible, but I wouldn't say with 6 kids I have more time!!!!
I hope this info helps someone, saving on food is one of the ways we save for Disney!!!