One good example are Indian riatas. These are basically a salad with plain (i.e. unsweetened) yogurt as a dressing. The first one I had was made from peeled, diced raw cucumber and onion with a little more plain yogurt than needed to coat. I usually remove the cucumber seeds as well, but you don't have to. It can be seasoned with just salt and pepper, or you can experiment with traditional spices: cumin, mustard, turmeric, coriander, and cayenne. This is a deliciously cooling side dish that's also low calorie. We've made it with the addition of tomato which makes a good complement to cucumber and onion. I've seen a recipe for a potato riata which uses potato, boiled, peeled, and, diced with plain yogurt dressing and a bit of cumin, coriander, and cayenne, which you can think of as Indian potato salad.
Indian curries are also a good option, especially if you're looking for low-calorie recipes. And by the way, you can buy the spices that make up the curry mixes separately (and probably more cheaply). If there's an Indian or Asian food market nearby, you may be pleasantly surprised at how much cheaper some of those spices can be bought in large packages. Traditional curries rely mostly on vegetables, but they can include fruits as well. And not only is India is a very diverse country, including many partial or non-vegetarians, but curries have spread into other countries, if you prefer your curries with meat. Apple and chicken often go together in curries. Beef curries are delicious too. Coconut milk and ghee are common in traditional curries, and those aren't exactly cheap in this country, but there are many recipes using alternates to those items. By the way, the riatas are a perfect side dish to a curry, especially if you like spicy ones.
Good possibilities are Mexican or Tex-Mex (depending on where you live) and some Asian and Chinese American and Italian dishes that rely on vegetables. Other cuisines worth exploring are North African and Middle Eastern cuisines that rely on legumes (Moroccan seems to appeal to Western tastes), other Mediterranean cuisines, and Jewish food. Some of the other Latin American foods are worth exploring as well as sub-Saharan Africa, especially if your family enjoys new tastes.
One of our frugal ethnic favorites is Matzoh ball soup, made without the matzoh. Think of Matzoh balls as a Jewish dumpling, traditionally made with a special meal and dropped into chicken broth. However, we discovered that, while not quite as good, saltine-type crackers can be crushed up and used in place of Matzoh meal (I should mention this substitution horrifies the friend who taught us to make Matzoh ball soup.) Since we can get a 1 pound box of generic crackers for less than $1 and proper Matzoh meal is usually several dollars for a container, this can be a nice savings.