I have always (35+ yrs) fed and entertained my family on $100/month.
Run out of money? (very seldom) don't eat (good solution). We often feed local seniors / shut-ins all within our budget. (And occasionally go without food ourselves, (very, very, rarely))
We homeschooled, so kids had to budget / cook / feed everyone on the same $$ (living on 4 different continents). It is really quite EZ. We eat LOTS of fresh fruits and veggies, (4-6 servings each / day).
I buy from a 'local' farmstand / commercial gleaner. Most fruits and veggies are less than $.50/# and are 'damaged' (bruised). My production costs are higher than that (I am also an 'ex-' commercial grower). I can't think of the last time I bought 'prepared' / convienence food. Not growing our own, at the moment but probably will need to with increased fuel costs. (farmers / transportation).
Freezer is full of CHEAP pacific Salmon, Sturgeon, berries, veggies. When we lived in NE, COLO, and WY, it was easier to get cheap and GREAT meat and veggies, but fruit was more. PNW has TERRIBLE beef, but the fish and lamb are good. It is possible for Yr Round gardening, which I may need to explore.
BTW... I also drive a $35 car that gets 50 mpg on free fryer grease. No need for dinosaurs or OPEC (since 1976)
Plan must have worked... one of my kids lived on $5 for 2 months while a senior in College. (was cleaning the cupboards and attending LOTS of free food events
) Money has never been the issue, we just prefer to give it to others rather than feed ourselves fat. (We are plenty FAT)