I personally know some folks who spend all their money on fast food, and then online it seems pretty common folks not knowing how to cook causes massive financial problems.
My super duper cheap meal that takes no effort is “lazy rice veggie soup”: Can of peas and carrots cooked with a bouyon cube until cube is dissolved Add cooked rice to mix, and heat until rice is flavorful with absorbed broth
I do a cup of dried rice, and a can of peas and carrots which means the soup has 800ish calories and I think it’s pretty good as it’s either 2 small meals that you can have sides with, or one large one!
So what are your cheap meals you like to make? The less well known, the better!
You are simply not going to find rare and cheap in the same meal. The best you are going to do is remind people of food that they haven’t had in a while.
Or you can define uncommon as food that people generally don’t eat. Insects, for instance. While bugs are incredibly common, most people do not consume them in great numbers.
Happy now? Sit down and eat your potatoes.
Not really since OP asked for something not super common and you answered with something really common.