I cook for myself, day in day out. Sometimes I'm motivated, other times, not so much. I'm not vegetarian, but I don't eat much meat (mostly because it's expensive, also because I enjoy vegetables quite a lot).
On a good day I'll cook a curry or stir-fry in the wok (buy the paste/sauce, add chilli/garlic/onion, 3-4 vegetables, and sometimes meat - chicken/lamb/kangaroo mainly). I usually do Thai curries (red/green/penang) so coconut milk, fish sauce, palm sugar and kaffir lime leaves are on hand. I'm quite partial to indian as well, and I'll do a tikka masala, or korma. With rice in all cases, very occassionally I do hokkien noodle stir fry. These are really easy to cook, a Thai curry takes me 30 minutes from prep to eat.
About once every 3 weeks I will do a roast - lamb usually, with roast vegies, this is super easy, I buy a marinated mini roast, cut up potatoes and pumpkin, coat with oil and all kinds of herbs and spices, chuck it all in a roasting tray in the oven, make a quick gravy and steam some greens on the side. Takes 2+ hours though (my oven is a horrible piece of ****).
I also do the meat + 3 veg thing about once a week, beef/lamb/pork steak (pan fried) with steamed veg (microwave).
When I'm tired and can't be bothered, I keep some quick-pasta in the cupboard, and some sandwich fillings in the fridge. When I'm really dog-tired I just crack a bourbon and skip dinner. lol
I work at a green grocer so every second day I buy a bag of vegetables, I'm quite partial to most of them, favourites at the moment are cauliflower, zucchini, beans, capsicum, corn on the cob <3, carrot, mushrooms and broccoli. I mix it up, my rule of thumb for any given meal is 3-4 veg, all different colours. Keeps it interesting and makes the plate look nice. :)
In summer I BBQ a lot, easy and fun with some friends over.
Expense wise, a curry/stir-fry costs me under $10, or a bit more with meat (serves 3). A roast costs me about $20 (serves 3) and basic meat+veg is under $10 too unless I treat myself to a decent cut. I don't keep track of my food budget really, but I guess I spend about $50 a week on meals I cook plus a bit extra for lunch at uni, breakfast cereal, bread, milk etc.