We're a dual working family with two kids (5 & 7) and long commutes, and it really is a struggle. I go through phases where I feel totally in control of our food, and times when we're not, at all. Still, there are some routines we use to cut costs.
I hardly ever buy fresh berries. They're just so damn expensive at $5+ for a tiny container. We have a strawberry farm near our house & grow raspberries/blackberries/blueberries, but for us fresh berries are pretty much only eaten in season. Our purchased fruit is generally limited to apples, bananas, mangos ($1 each), kiwis (4 for $1), and clementines and grapes when they are on sale. Peaches are also grown locally, so in season those are inexpensive, and last year I bought 10lbs of figs for a song. However, frozen berries are cheap, and my kids love them, plus no worries about them going bad before we get around to them. I generally pour some into a bowl and let them thaw in the fridge, but you can also defrost in the microwave.
Breakfast & breakfast-for-dinner: I got my kids used to regular rolled oats and plain unsweetened yogurt early on. They get jam, maple syrup, or brown sugar on top (plus frozen berries or fresh fruit), but they aren't used to the expensive individual prepackaged ones. I also keep a big canister of plain instant oats, which are super cheap and microwave in one minute. Sprinkle some cinnamon, brown sugar, and frozen blueberries on top, and the whole thing takes under 3 minutes, great for busy mornings or evenings. Scrambled or fried eggs take almost no time, add some fruit and either sauteed or raw veggies (I love doing garlic spinach), and maybe some whole grain toast. Or make breakfast sandwiches with some ham, egg, and avocado. Or huevos rancheros (eggs with salsa/beans/tortillas).
Frozen veggies are awesome and extremely cheap. I always also keep a few bags of frozen easy stuff, like fries, tater tots, and fish fillets. I can throw 2 sheets pans in the oven - one with fries, one with fish fillets - and we have a no-fuss dinner in 30 minutes. It takes a while but is completely hands-off. Frozen peas, broccoli, spinach, and corn cook up quickly in a pan. Frozen stir-fry mixes + tofu or chicken + pre-made teriyaki or other sauce makes for a fast meal. We also often do just cut raw vegetables instead of a cooked vegetable side, usually carrots, cucumber, and bell pepper, or a quick salad.
Canned beans are also a really easy/cheap way to make dinner. I'll throw canned black beans, canned or frozen corn, and some chili powder, salt, & cumin into a pot. Cook for about 10 minutes, then pile into tortillas with vegetables, salsa, cheese, sour cream, guacamole, or other toppings. Or you can use the same black beans to make nachos, quesadillas, or burrito bowls.
I cook big batches of rice at one time because it takes so long to make, then I'll use it for burrito bowls, stir-fry, and fried rice over the next 3-4 days.
Sandwiches or wraps are a perfectly acceptable dinner. "Snack Plates" are a perfectly acceptable dinner - put a protein, 1-2 veggies, and a fruit on a plate, then add some other stuff you like. There are infinite variations. Maybe the protein is pre-cooked cold shrimp, previously grilled chicken, canned tuna, smoked salmon, canned beans, hard boiled eggs, a bowl of yogurt, or some cheese. Veggies can be leftover cooked ones or raw. Add some guacamole, dip or dressing for raw vegetables. Add fresh or frozen fruit, and maybe some crackers or bread or pita. Maybe throw on some olives or pickles. They can be themed or totally random, and it's a great way to use up those odds and ends of food in your fridge with no cooking required.