I thought up another good portable lunch possibility. The styrofoam bowls that come with ramen noodles. Need access to hot water. You can get the kind that have dried veggies in them. Pull open the foil top. Pour in hot water. Seal it back up and wait. Eat it straight out of its own bowl. Meal and drink all in one. I have tried a couple of different types. Good hot meal for less than a buck fifty.
I enjoy those too. Probably more often than I should.
These are my favorite ones. I also like to mix in a tin of sardines.