Unprepared foods, in the US, are much cheaper than prepared foods.
A bag of Cheetos (16oz) is $5.
A pound of chicken legs is $2.
2 lbs of rice is $3.
I'd suggest you instead argue that low income people work multiple jobs and therefore have no time to cook. I've had this debate a lot before.
"I can't work out, I can't afford a gym! No, I'm not going to run around the park or join the YMCA!"
"I can't eat healthy, I can't afford it! No, I'm not going to buy a big bag of rice and black beans."
Before anyone comes at me: there are poor people and their struggles are real. I am 100% opposed to things like removing soda from food stamps.
https://fred.stlouisfed.org/series/APU0000706212
It's currently at $1.82/lb. Assuming that 30% of leg weight is inedible bone, it's more like $2.60 per pound of edible chicken.