Especially on a budget, the chips, shakes and bars are the least efficient way to eat, IMO.

I usually buy up meat on sale, as well as cheese, eggs, tuna, chicken (particularly drumsticks and thighs..usually well under a dollar a pound) frozen veggies are good, like broccoli and cauliflower to go with your salads.

Honestly, you don't seem to be eating nearly enough, and while it may work for now, you'll likely hit a snag down the road a bit.