It's far cheaper to 1) buy unprocessed foods at the grocery store, 2) spend $20 a few times for cookware that will last plenty long enough, and 3) cook for 20min a day or do more preparation on the weekend. It doesn't require becoming a professional chef or buying appliances.
I think the main problem is that fast food is addictive and those who are vulnerable to that tend to make excuses for why they can't stop.