The old classic beef roast with Campbell's cream of mushroom soup and dry Lipton onion soup in a slow cooker is #1 in my book. Follow the recipe on the can and/or box, add your veggies, and it'll all be gone before you know it.
Bonus food - back when I was a kid my mother would make "pennies & potatoes", which is just hot dog slices and diced potato done in a skillet with a little salt, pepper and garlic. Butter or olive oil, whatever you've got. Crushed red pepper if you're in the mood. Great cheap food.
