Roasting a whole chicken is very easy and you can serve it with a salad, steamed broccoli or some other vegetable. Use leftovers for sandwiches, wraps, chicken pot pie, quesadillas, etc.
Baked salmon, sweet potato or squash, salad, and quinoa or couscous is a very easy meal to prepare.
I like to make quiche. Buy a premade pie shell, blind bake it, then mix 6-8 eggs with whatever you like, pour into shell, and bake until set. I usually add very finely chopped kale (lots), sauteed onion and garlic, crumbled feta cheese, salt, black pepper, and maybe bacon or prosciutto. Then I put sliced tomatoes on top and bake.
Just think of easy lean proteins, vegetables, and complex carbs to make in various combinations. An acorn or butternut squash cut in half and cut into .5" slices, drizzled with olive oil, sprinkled w/ salt and pepper, an\d baked until soft is simple but good. Baked sweet potato fries are also pretty good.
Try to make a salad with every meal. It fills you up so you eat less of the more calorie-dense foods and you will tend to have more leftovers for the next day. Bagged salads are good for time-saving, just make a vinaigrette with olive oil and an acid like balsamic vinegar, apple cider vinegar, lemon juice, etc. Add thyme or other herbs, citrus, honey, salt, pepper, mustard, whatever you feel like. Mix and add to salad. Add chopped apple, pear, walnuts, blue cheese, raspberries, sunflower seeds, chicken breast, steak, radishes, whatever.
Just keep it simple at first and you'll learn as you go. Fill up on vegetables, then protein, and a bit of carbs. If you have leftovers, portion them in tupperware containers for lunch. You'll save money on lunch and also eat healthier.
The biggest thing is to plan ahead. Don't shop every other day and have a week of meals planned in advance. You will save money (more shopping = more impulse buys) and eat healthy, because you won't fall back on eating out due to lack of ideas/being too busy.