I found that a breakfast meal was the easiest to shop for. The gas station had a lot of snacks and drinks. They didn't have any vegetable selection; not even frozen vegetables. Pretty much all of there frozen items were microwaveable meals like pizza rolls, or frozen meals like pizza.
Looking around the store, I found family size soft wheat bread for $1.99, Honey Ham for 99 cents, 1% low fat milk for $2.49, dozen eggs for $2.19, and a fruit cup for $2.59 (2 @ $5.18). I assumed the family would have staple ingredients of butter, salt, pepper, and oil. The meal came out to $12.84, which is under $15!
I toasted and buttered the bread, and placed ham on top of it. Then I friend the eggs sunny side up and salted and peppered them. Then I placed them on top of the toast with ham. This was eaten with a side of fruit, and a glass of milk.
The picture shown is an example of what the meal would have looked like. I didn't actually purchase the ingredients because I already had most of them at my house. In this picture the ham is replaced with salami. Also, imagine assorted fruit on the side.
I found this meal to be quite filling, and you get your protein, grain, dairy, and fruit. The only thing missing is vegetables...
This meal was only supposed to be meant for two people, but with a dozen eggs, a loaf of bread, and a half gallon of milk, you could easily make this meal for more than two people. However, this pricing is based off only getting two fruit cups (enough for two people), and the package of ham didn't contain much meat.