When I was in college, I had the rule of not buying anything that is >$1.50 per pound. This is what I was reduced to (prices may be different now due to inflation and geo area):

1. Apples, oranges, grapes, strawberries when they are on sale
2. Milk, yogurt
3. Pork shoulder, chicken quarters, thighs, drumsticks
4. ground pork, ground beef
5. Carrots, broccoli, potatoes, cabbage (you’ll be surprised at how good thinly sliced cabbages taste in a sandwich)