Most food has 200-600 calories per pound, so you need 4-6 pounds of food per day. (This lines up with Google search.) Call it 35 pounds per week. Therefore, you need to spend an average of $1.50/lb to hit $50/week. Bananas and canned tomatoes or beans are well under $1. Pasta and bread are $1. You definitely don't have to give up all TV dinners or meat, you can eat pretty normal.
That does give me some food for thought. To take an example I cook regularly, the absolute cheapest tomatoes are a bit under $1.50/lb, but San Marzano tomatoes are more like $3/lb, and worth every penny. Then, if you're making a basic pasta marinara, add garlic, thyme, oregano, maybe some pepper flakes, olive oil... No one thing is expensive, but it adds up. Then, if you really want to kick it up a notch in the cost department, add some fresh thyme and basil. Now you're at something like $4-5/lb for something that is nutritionally very similar to the $1.50/lb version, but damn is it ever going to taste better.
I guess to some extent I'm asking to have my cake and eat it too. It just seems like you have to give up most meat and a lot of flavor to hit $50/week or lower.
