I usually do the same. I maybe spend 2 or 3 bucks, you really don't need to spend any more though.
THANKFULLY I've lost interest in fast food, maybe it was just a childhood thing but I just can't enjoy it anymore.
Mostly all I eat is cooked chicken breast with wheat free breads and mustard, corn flakes with 100% optimum nutrition whey protein powder mixed in water (phucking bomb with a few packets of slpenda, WAY less sugar than milk, great energy/fiber combo, though a bit high in salt).
Maybe once a month I'll eat beef broccoli and chicken fried rice or a burrito from a good taco shop, which is on the healthy side of the sh*ty food chart.
The dollar menu is great when you need to feed yourself some fats though, a doubble cheeze burger from McDonalds holds me for about a month as far as fat intake goes 😀.