Haha makes sense! I forgot I posted it, but as an experiment I actually did this just to see how hard it is.
https://lemmy.world/post/17890870
But I mean the main things you need are calories, vitamins, and complete proteins. Flour is the cheapest calorie you can get in the US, so cooking your own biscuits, tortillas, sour dough, and gravy will always be the most calories for your buck.
Soy is a complete protein by itself, but rice and beans together are as well. Rice and beans is also a king of calories per price, so there is a reason I put it on there, and a reason you are alive it sounds like it!
The last thing is vitamins from veggies/fruit. In my post I used small amounts of dried fruit in oatmeal, peas in gravy, then tomato sauce. So getting a mix cheap frozen/canned/dried fruit then having a bit of that each day will help. As will making gravies/sauces with different veggies/stir fries.
I was able to do it under $2, and I might try it again with all different meals to try and make sure I can practice what I preach. I make one off cheap meals a lot, but don't always do a full day.
Straight up I was conservative as a young teen, because that's what EVERYONE was here in Utah when I was in the LDS church.
Now I just keep floating more and more left as time goes on.