Chain restaurants often times will be more expensive than small, hole in the wall places. Part of that is the price of rent that gets passed onto the consumer. If you have the option, I'd say try to find a taco truck, food window (no seating area), or grab and go food from a grocery store.
If you're in Seattle, Dicks Drive In is still relatively cheap compared to McDonalds.
Dicks isn’t far behind really. But in far more willing to spend my money there because the food quality is so much better and they do a great job taking care of their employees.
They used to sell a T Shirt that said that and had the Dick's drive through logo on it. They might still sell it, idk, I still have mine so I never looked to see.