People repeat the myth that healthy food choices are expensive (they aren't) and time & space consuming to make (they can be) so often that most people believe it. But it just isn't so: you can eat at McDonalds every day, and if it's only a part of your diet, it's healthy. If you can get fibre and some vitamins elsewhere, and aren't overeating, the protein and calories in a fries and a hamburger are fine. Good, actually.
Healthy foods are simply principally marketed to, sold at a large markup to, middle to upper class Americans so they believe that's the usual market value.
Now, it can be expensive in time, effort and equipment for struggling, hard working, irregular shift workers. That's a different issue though.