Establish a kitty early and require double for the first shop. Then, by agreement, use this to go to big cheap Indian and Chinese grocery shops on the outskirts of your university town and bulk-buy spices, noodles, lentils, rice, and dried fruit in large bags. This will save you a lot of money over the next year. Recommended: 500g sesame seeds, at least 250g paprika, cumin seeds, ground coriander, turmeric, garam masala, salt; 50g chili powder, cinnamon, fenugreek, mustard seeds, black pepper. Also soy sauce, coconut milk and a couple of concentrated sauces that you don't have to chuck after a week (read the label carefully to make sure they're the longlife kind) for those of you who find cooking quite challenging. Black bean, plum sauce and tikka paste are my suggestions.
Find out when and where the best streetmarkets are for fruit and veg and use these over supermarkets.
Agree with your housemates that, on top of the usual kitchen stuff which you may already have, each of you will provide at least one of the following: cheap hand blender, wok, kitchen scales. The slow cooker idea given above is also very good if you think you'll be in the house for the early afternoon to do the legwork for the evening meal, and you are up for it. It won't work if your college and library are a bus ride away.
Be aware that what is cheap in supermarkets is not always likely to be the best nutritionally. Real cheap "superfood" exceptions include: chicken (every chicken should make you a meal one night and chicken soup the next), carrots, lentils and beans cooked from scratch, porridge oats, free range eggs from Iceland (£1 for 6), brown rice, barley for soups.
To avoid wasting money on tasty lunchtime sandwiches, keep pittas in the house. These can be quickly filled with fingerfuls of tomatoes, onion, tinned beans, bits of cheese and leftovers, tinned tuna, etc., slathered in homemade Italian dressing (just 3:1 olive oil and balsamic mix), wrapped in clingfilm and popped in your bag in the mornings.
If any of you eat tons of carbs, it is definitely cheaper to cook a lot of porridge (delicious with bananas/dates added during cooking) than to eat bought cereals, and homemade rice pudding is also cheap and yummy. Artisan bread with proper peanut butter is really filling; so maybe one of you might try learning breadmaking...
Don't put nuts on the kitty. They are brilliant, but expensive so need to be bought in bulk (Holland and Barrett offers are best), and one of you will munch the lot and cause bad feeling. BUT they won't go off if you buy a pack of wooden clothes pegs and use them to seal opened bags, so no need for tupperware. Ditto the other storecupboard groceries.
Spaghetti is about 25p in the Asda basics range and about 3 times that in most other standard supermarket ranges. Real feta is about 2.5 times as expensive as virtually identical "salad cheese" (but I would only buy real parmesan, ungrated). I could go on... but now I have another life...