Mine are usually something like flour, butter (or like butter, real stuff is expensive), many pastas, maybe some frozen meat, hella potatoes, and I have acquired many spices over many years. I usually have a giant container of oil from some time past when I needed it for something and just bought the big one, so I can easily just bread and fry something. Potatoes come in a million shapes and sizes. You can portion what little meat you have and put other things in too (such as the potato), and mix with various pastas. Luckily, pasta is all the same in flavor, so it doesn't matter the type. I can make a rue from the flour and butter, and bc of my coffee addiction, I always have creamer, so add that into the mix, season, add to whatever. I also tend to have large amounts of rice, bc much like pasta, rice is for when I am broke.

Basically, my poor people food go too's are :

Rice Pasta Potatoes Flour

After that, the items become luxury. I find the cheapest version of whatever food I don't hate, and do kitchen witch shit, and magic up some sort of meal out of it. Eggs used to be cheap, so that was a constant til recently. Chicken too. Went from like twelve boneless skinless thighs for 6$ to more than double that. Bummer lol I guess ima have to figure out how to make myself enjoy pork (if it's still cheap idk lol)

Good thing to do is, when you have the funds, buy things you can incorporate with one another in a bulk size. A thing I've found is sriracha, soy sauce, and sesame oil. Most expensive part is the oil. BUT! It lasts a while. You can mix approximately half soy and half oil, and give a boost with the "hot" sauce, and you got a really yummy sauce for your rice (or whatever you want tbh).

I also always have stocked some form of brown sugar. Lasts forever. I usually melt butter, add the brown sugar, and throw a little red wine vin, and man that makes some yummy chicken. Add seasonings however ofc, salt pep garlic (classic).

Honestly I eat poor most days, but the key is buy bulk items you can incorporate w each other, when you can. You'll have a surplus of it always, shit goes a long way. Rice for every meal sucks, but there are tons of ways to make it. Cooking takes creativity, and it can be done on a budget. It ain't easy, but there are tons of tutorials and recipes online that can help if you get lost.