I understand that some people don’t like to eat leftovers but when you are saving money on food, you cannot let anything go to waste.
any type of sandwich fixings that you might have on hand or find at the store on sale. Mind you, deli meat is not cheap.
Any type of pasta salad you want. An Italian pasta salad with cheese, pepperoni, Italian dressing, and veggies. Or the mayo, tuna, and peas type are both great for lunches. You could even make a bacon ranch pasta salad with bacon bits pretty darn frugally.