This was a favorite when my kids were younger and it was cheap too. It freezes well and can be reheated in the oven or microwave.
1 lb of lean ground beef
1 can of cream of mushroom soup
1 can (fill soup can) of milk
1/2 bag of frozen tator tots
1/2 bag of frozen peas
3 oz of cheese (optional)
Brown ground beef and drain. Combine soup and milk, mix thoroughly. In a 13x9 pan mix ground beef, soup mixture, tator tots and frozen peas. Sprinkle cheese on top (Optional) Bake at 375 for 40-45 minutes. Remove from oven and let set for 5 minutes before serving.