It’s not the cost of the food, it’s the skill level and time it takes to prepare simple and fresh foods vs. slamming something into the microwave. If you’re working long hours at low paying jobs, the time can be a problem.
Some meals can be prepped in downtime and frozen for later use. In the colder months, for example, I always have several small containers of frozen home made lentil or split pea soup (my faves). It's never more than 10 minutes away from ready and it's home made. Soups are always better the next day, or after frozen and thawed.
Time is a problem, but quick healthy food is doable. I found that fresh veggies microwaved and then seasoned with a butter substitute & lemon pepper is great, even for a snack. Gorton’s has a line of grilled fish are good. In our local supermarket we can get 10 microwaveable entrees with low fat for $10. You can even do dessert. Klondike has low fat ice cream sandwiches that take great!
Slow-cooker. 8 hours on low for things like beef stew, pot roast, pork shoulder, plus it makes low-cost cuts of meat quite palatable.