I have a cheap and yummy meal from student days, is great with rice or spuds, with cheese or without.
Tin budget toms
Tin budget beans
one pepper or mixed frozen peppers are cheaper
one onion
garlic 2-4 cloves
Some mushrooms
Dried herbs any combination
Dried chilli flakes or just powder to your taste.
Any other veg such as sweetcorn, courgette
Can also add some sausages for cheap sausage casserole.
Very cheap and dependent on your larder/fridge
My husband and I survived on very little money during our PhDs, ate very well and ran two very good marathons.
Home made flapjacks are very cheap, own brand cereals are cheaper and taste the same.
Make all sauces instead of buying jars, tin toms and dried herbs are much cheaper than jars of curry, chilli or pasta sauces.
Tinned tuna and mince are your best friends!