My advice would be to keep it simple. You can focus on making sure every meal has some healthy carbs (such as filling whole grains), some protein, and some vegetables. You can also make meals on the weekend to last for several days ... or, perhaps, make things that can be reused in different ways. If you cook rice for a stirfry one night, the next you can use it in a different way.
Stirfrys are pretty simple, just make some rice and saute your protein and vegetables, add some flavorings, maybe just a bit of soy sauce, garlic and ginger. Or some orange juice with soy sauce.
Canned tomatoes are also immensely useful. For a pasta sauce, you can saute garlic and onion and add chopped or pureed tomatoes, add some dried basil and/or oregano and cook for awhile. This is pretty versatile, you can add any vegetable you want. Spinach, mushroom, zucchini. For some protein, it works well with lentils or meat. make enough for several days, maybe if you get sick of just plain pasta and sauce you could toss it with a bit of mozzarella and bake, or try adding different things on top such as feta or fresh parsley.
Buying vegetables in season is a good way to avoid spending a lot of money. Asparagus is in season right now - easy to roast in the oven tossed with olive oil, salt and pepper. I find it nice with pasta, lemon juice and garbanzo beans, but you can also serve it alongside a meat and maybe some rice or bulghur.
I imagine you don't have much time to cook, but another thing that can help with cost is using dry beans. I tend to make a pot of beans on Sunday and use them in different ways throughout the week. Wrapped in a tortilla along with some cheese and vegetables such as tomato, onion, broccoli or spinach and then toasted. Can be used in soup, in pasta, Mexican dishes, salads. Great to have a salad of rice, beans, and whatever vegetables I feel like. Very filling and can be different every day.
One thing I would avoid is finding recipes that call for all sorts of fancy sauces and spices and pastes which then fill your cabinets and fridge and never get used. Pick the ingredients you want first, then find a recipe that uses only things you have. If you've stocked up on the things you like, then you shouldn't have a problem.