if you’re starting from nothing in terms of food here’s my list. whatever you can get cheapest of the following beans/lentils/chickpeas/tofu. vegetables. rice. onions. cooking oil. salt. Go to small shops for produce and a bulk store if you are near one of tried stuff. you can often get spices for very cheap from bulk stores as well. if you have nothing to make your food have taste good you can often get free sauce packets from fast food places if you ask nicely.

this might be very regional advise so sorry if this isnt helpful