My kids like any kind of pasta. I go Marc's. Do you have one near you. Anyway they always carry cheap and different pasta. Some easy cheap sauces I make are:
Alfredo sauce
2 T butter
2 T flour
2 c milk or (1 c milk and 1 cup chick broth)
1 8 oz package lowfat cream cheese (neufchatel)
salt and pepper and parmesan to taste
Melt buter in saucepan. Add flour and stir to blend, cook while constantly stirring for a minute. Add mild and cook while constantly stirring until thick. Add cream cheese and whisk or stir until smooth. Pour over hot pasta. I have the sauce ready before the pasta so I can pour it over immediately. I also do not drain pasta completely, leaving about 1 cup pasta water in pan. This is a mild sauce. We like mafalda pasta or a short curly pasta.
Broccoli sauce
1 head broc chopped
1 can chick broth, add a little boullion and more water if necessary to barely cover broc
milk
velveeta cheese to taste, at least 2oz
Boil chick broth and broc until very tender. Blend until smooth. I have an immersion blender and this works well. Add milk to make consistency you like. Add velveeta until melted. Put sauce on top of pasta. We like barilla campanelle for this. You can also add carrots to the broth.
I also just boil any pasta and drain it and add a can of chicken broth until absorbed. My kids like alphabet pasta for this.
My kids also like pita, tortillas, naan, lawash, flat bread and often these are high in fiber. You can add whatever toppings like: refried beans, hummus, cheese, salsa, meat, veggies, pizza sauce, pb, jelly, honey, salads, chicken nuggets, bacon. The list is infinite.