Have you got a pressure cooker? What about fridge, freezer?
Dried pulses are good.
Dahl, refried beans, bean chilli.
Couscous (dried fruit and stock cube), risotto (with stock cube, nuts and peas).
Don't forget the humble baked bean. Try and stock up on eggs and cheese in the last month you are paid. They'll keep well in the fridge and brighten the rest of the food.
Porridge with UHT milk, or skimmed milk powder.
With oats, sugar and oil you can make a decent flapjack. With tinned fruit, a crumble.
Veg like cabbage, onions, swede and squash keep well if you have space.
I grow carrot/parsnip tops, the end of the celery, and lettuce bottoms to get some greens.
You can sprout pulses as well. Urid beans work well.
I did a no shop lent once, to see if we could manage on store cupboard stuff. It was fine.