The men in my family use crock pots. They cook soup, stew, roast, chile, beans etc. on Sunday or Monday and eat from that all week. I personally like more variety. I add salads and just about any kind of veggie in season. Taking a lunch to work is very is very economical. Don't buy drinks when you go out to eat unless water costs the same as every other kind of drink offered.
When all else fails Taco Bell.