Store cupboard

My nan was the one that taught me the importance of a good store cupboard, you can make the most mundane of ingredients in to something great with a few store cupboard basics. If you are in halls or a shared house then your store cupboard may well be a cardboard box in your room, just remember to put the box away from a radiator to make sure things last.
I will keep adding to this as I go along as I remember things or as I add recipes.

Tinned chopped tomatoes  (these don't have to be expensive especially if you are adding spices, buy the basic ones)
Stock (I use marigold, it comes in a tub and so you can adjust how much you add which makes it cheaper in the long run, also if you are vegan or wheat intolerant then they do a variety for you too)
Soya Cream (Most people turn their nose up at this without trying it, but a cream you can keep in the cupboard is great for making sauces and you can't taste the difference in a sauce)
Salt and Pepper (always surprised me how many students didn't have these)
Herbs (If you can only buy one lot of dried herbs then herbs de provence is a good one that you can use for most things, if you have room and budget for a few more then buy thyme, oregano and dill too)
Spices (Paprika, cumin and curry powder are your basics after that it depends on what food you like, look out for deals on tubs of spice mixes for cuisines you like, moroccan for couscous, thai 7-spice for stir frys, etc)
Oil (If you only buy one oil make it a flavourless one such as sunflower, you can use it for cooking as well as salad dressings)