Honestly, you will get so many disparate answers/responses to this... it just is so variable depending upon where you live and what you consider healthy meals.
At our house, we don't eat casseroles (generally). If we have a meal at home it typically consists of a meat (grilled or baked), a green veggie or salad, a grain (sometimes--either corn or brown rice) and sometimes a baguette of bread with olive oil. We do not eat a lot of pasta. We do eat chili with organic chips or baked potatoes, with shredded cheese.
But, I have teens, so it take a lot more food than you normally would need. We also eat out a lot--which sometimes makes planning meals difficult, b/c if I buy fresh veggies/salad components, they don't always last from one mean until the next, due to kids after-school schedules/activities, and husband's work schedule. We pick up dinner out several times a week.
We also pack lunches for husband to take to work (fairly elaborate salads with spring mix, red bell pepper, carrot shreds, cucumber, sweet onion, cherry tomatoes, pepper jack cheese, sunflower nuts, and ham/turkey), and school lunches for teen daughter who will not eat a school lunch (fresh apples, peanut butter pod/cups, pretzels, mandarin oranges, peanut/mixed nut packs, etc).
And depending on what you do for breakfasts, you could spend or save a lot of money. Prepackaged cereal and milk can get expensive if you eat it every day. But a carton of eggs is less expensive, and better for you, if you make eggs and a piece of toast.
I also have a husband who makes protein smoothies DAILY. Smart balance peanut butter, greek yogurt, whey protein powder (chocolate), banana... and snacks on cups of greek yogurt for his daily dessert. He takes Zone bars to work for a snack.
All very healthy. Also pretty spendy to keep stocked on a regular basis.
But, if you chose to have your household snack on baby carrots, you could snack a lot less expensively, and buy that item in bulk more easily than I can buy Zone bars.
So, my point is, there is no real way to answer the question. It all depends on the choices you make, what your household budget is, where you live and food pricing, what might be called "reasonable."
I spend a ton of money on groceries every month. No one in my house likes a bagged apple (they are almost always bruised and mushy, and no one eats a mushy apple), but everyone eats apples.
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@IamAKat: that was my first thought, too-- what leftovers from a roast chicken? There is no such thing at our house.