Hole-in-the-wall ethnic food shops/take out are the way. If you want 'murican fast food, you gotta break the bank… but find a little family owned taqueria that does their shit right and you can stuff your face with the best tacos you’ve ever eaten for like $3. Highly dependent on your local options ofc, so keep an eye out.
In my experience, the sketchier the restaurant looks, the better the food is.