It's a good question and I'm equally curious to know the answers. I used that particular example just to compare prices of a nutritious vegetable versus junk food (because at that price, really, I doubt the pale melty bits on top of the pizzas are real cheese). While food is generally cheaper in the US, the principle is the same. I've never been rich but I have been poor, and I can definitely say people with more money have more options.

Is it cheaper to eat fast food than to cook at home? With McDo's dollar menu or a Subway 2€ sub, yes, it can be, especially for only one person. It seems like the more people you're feeding, the greater the potential savings when cooking at home.