I've found that, to a certain degree, "cheap, healthy, tasty, fast -- pick at most three" seems to (often) be the situation I find myself in.
Well, that's sort of to be expected. :-( All the foods you've mentioned are highly processed, and engineered to be shelf-stable, tasty, and use cheap, good tasting ingredients. I wouldn't even consider them food anymore, more like highly engineering edible dopamine stimulators.
Opposed to that, a grapefruit does not stand much of a chance. But if you kick processed sugars for a few weeks, things start slowly tasting better, or so I hear. I've been trying to do that, but sugar is in almost everything these days
If it isn't convenient (timely and open at desired times), tasty, and inexpensive it won't compete on the three metrics that the actual competition is winning on.
I'll agree they're abundant, but are they actually cheap? How much money in those products do you have to eat to feel full, vs healthier food?
It's easy to pound down snack foods and desserts but still feel snacky, and that's just flushing money down the toilet while adding to your personal carry-on burden.
One of the things you have to realize is that if you're trying to save money, you don't get to eat what you want to eat all the time.
That's like saying "It's much more expensive to eat fresh produce, my two favorite are foie gras and truffles, and those are fresh, but not cheap."
Most people (in the world) eat a diet of starches and pulses with some spices. Considering how cheap beans, rice, and vegetables are at ethnic markets and farmers's markets, eating healthier is more time consuming, not more expensive than eating crappy food.
Of course, you'll have to give up on the fact that you can have raspberries year round. Raspberries are a seasonal fruit, and in season, they are cheap as heck, are as all produce.