Best CHEAP options?

What are some cheap options that are nutritious? I’m seeing a lot of highly nutritional recipes on here, but not cheap. And I mean hella cheap. Wearing the same pants 5 days in a row because you don’t want to buy detergent cheap. Not using the AC on a 100 degree day to conserve your gas cheap. Walking to the grocery store with a cooler to save gas money cheap.

My go-to for mega cheap is a can of mushrooms and a can of black beans in the microwave. If I’m 1-mealing it for the day, then I’ll add a half pound of ground beef. It’s about $1.20 and around 400 calories. Food is ridiculously expensive right now and I do not make a lot of money .

I’m talking $3 or less for the whole day. I usually only eat dinner so shooting for the 1200 calorie range.

Thanks.

Edit: I very much appreciate the advice received so far and have written some down – I want to make it clear I am not too poor to afford food without government aid, I am just incredibly cheap/efficiency minded .

Best CHEAP options?