I stayed with a friend in Houston in November and December. We went to a farmers market selling plenty of produce, nuts, etc that we put in our bags we brought. I spoke to one of the farmers a bit and he gave me some free vegetables. I find that pattern happens a lot.
I was full of envy because by that time of year, New York, where I live, has mostly cabbage for greens. Your local farms had a variety of greens in season (meaning plentiful and cheap). I'm pretty sure I could eat cheaper in Houston than here.
We also went to a store called HEB with a huge bulk section. We filled bags we brought with us.
We ate delicious, healthy, nearly package-free at low cost.
I'm not sure what you tried, but I find experimenting for a week or two doesn't give enough experience to learn to cook from scratch fast and cheap. For example, learning to cook beans from dry in a pressure cooker is fast, simple, and very low cost. Here are reviews of my famous no-packaging vegetable stews that resulted from my experiments: http://joshuaspodek.com/food-world-reviews.
> If it really, truly cost less to go without plastic, poor people would do it, they do any and everything to save a dollar on food.
I suspect causality goes the other way, at least in part, that eating habits, prompted by poor education and predatory marketing, contributes to them being poor. As I understand it, your logic would suggest that poor people wouldn't drink alcohol, but I see lots of alcohol stores in poor neighborhoods.