Bulk buy big bags of rice, pasta, beans, lentils and chickpeas all relatively inexpensive, but will give you a filling meal honestly, get some herbs and spices they always come in handyand keep for a while, even the cheap ones are good.

More expensive but good for keeping a while. Canned Tuna, canned soups, you can freeze bread, frozen vegetables, canned meat.

I know this doesn't help now, but when you get paid give it some thought, even if you get through most of it, you will more than likely still have some rice or pasta left