I have a theory that there is a impossible trinity (like in economics), where a food cannot be delicious, cheap and healthy at the same time. At maximum 2 of the 3 can be achieved.
Is there any food that breaks this theory?
Edit: I was thinking more about dishes (or something you put in your mouth) than the raw substances
Some popular suggestions include
fruits (in season) and vegetables
lentils, beans, rice
mushrooms
chicken
just eat in moderation
Edit 2: Thanks for the various answers. Now there are a lot of (mostly bean-based) recipes for everyone to try out!
Also someone made a community for cheap healthy food after seeing this topic!
Yeah only cheap if you don't include your time. And the cost of land. But as a Florida food gardener - OKRA is like nothing else. It grows even in the summer here, is beautiful, the flowers are lovely and my whole family loves it. If you grow it, you can pick them when younger, and the few you inevitably miss, save for seeds. Nutritious and delicious, and in hot climates, cheap.
Beans are the obvious answer to the OP's puzzle though. Beans and rice, build up your spice cabinet, endless variety and so delicious, cheap, and healthy.