Yeah, I'm not really sure what the long play is here. $200 is what I spend on groceries for an entire month.
A pound of chicken breast, a pound of apples, a third loaf of bread cost at least $7. And that's only 1500 kcal.
Under $200/mo is relatively easy to achieve as long as you know how to cook or can tolerate a repetitive diet. Stretching it to $250-300/mo takes it up a notch and makes it a very balanced and varied diet with whatever fruit and vegetables you want. I only run it up to $300/mo when I buy higher quality meats at Costco and eat an avocado a day.
Yes, beans/potatoes/rice can get you a long ways.