looking for low cost or free food

i feel like every time i post here im in a crisis 💀 but my dad is really really bad with buying groceries, like laughably awful. we get groceries maybe once every two or so months. our eggs are a week or so expired and we have nothing else to eat besides some packets of oatmeal and his leftovers that im not allowed to touch. i work for him and get $20/day for food but this is clearly unsustainable because i don’t eat breakfast or dinner, and it leaves me with no money in my paycheck.

unfortunately he complains about the price of groceries and other stuff a lot so i’d rather just find food or something so that i have something to meal prep and can eat breakfast too. i just need basic necessities like bread, pasta, maybe vegetables or fruit, milk, etc. if anyone knows where i can find them for cheap or free 🙂