Most grocery stores these days have a selection of fresh foods for sale that are fully or mostly pre-cooked. All you have to do is warm them, maybe mix some ingredients.

For example, Costco has some street tacos, stuffed peppers, and various other options.

I recently picked up some chicken enchiladas from Smiths and they are really good. They have both red and green. I prefer the green, but both are good. 2 large enchiladas for about $8. Easily enough for 2 lunches. They are fully cooked, just need to be warmed in the microwave for a couple of minutes. They don't have a bunch of filler in them - just generous amounts of chicken, cheese and the sauce along with some olives and onions. Much better than a $4 frozen meal.

You guys have any go-to ready-made lunches?