i bought 4-days worth of food for about 15$: raisins, peanuts, beans, and oats.
It's boring and probably not too healthy to eat only those for 4 days. it's not healthy to eat the same foods all the time, as variety is important for getting all the different types of nutrients, vitamins, and minerals. my mom sometimes gives me different food though. and after the 4 day, i'll buy other different foods, including dairy.