Which is the cheapest for groceries between Spar, Checkers, and PicknPay?

Hello, M21 here, my cousin and i live on our own. We're working with a budget of R1000 for groceries that will last us for the next 2 weeks (hopefully more).

We have about 3 stores close to us where we can buy groceries which are checkers, spar, and PicknPay, which one of those options would be the cheapest? We have a woolies here too but I know they're pricy.

Right now im just looking for meats, veggies, and spices.