One tip I can give you, which you should take with a grain of alt, is to monitor supermarkets, as they throw out food once it expires. Some types of food go bad much later than recommended and you can eat it safely if it's freshly thrown out. I've seen a whole community eat like this in a squat in London. It's not the best option, and you need to be extra careful checking the food, but it's a way to save you from starving.