Eat at least 400 g of fruits and vegetables per day, with the exception of potatoes and other starchy root vegetables.
Make sure that fats account for no more than 30% of calories consumed per day.
Eat no more than half a teaspoon of salt per day and limit the amount of sugar in the diet.
Don't forget about protein. According to the norms of Rospotrebnadzor, it should account for 12-14% of the daily calorie intake. Their remaining share is covered by carbohydrates.

In order not to get confused, remember that an adult man should receive 75–114 g of protein per day, 72–127 g of fat, 301–551 g of carbohydrates. The norm for women is 60–90 g of protein, 57–100 g of fat, 238–435 g of carbohydrates.

For children, the general recommendations are the same as for adults: more fruits and vegetables, less sugar, salt and fatty foods. The intake of proteins, fats and carbohydrates varies depending on age. For example, children older than one year should receive 39–87 g of protein, 44–97 g of fat, and 188–421 g of carbohydrates per day.

It is also worth making sure that the food contains enough fiber: for adults it is 20-25 g per day, for children - 10-22 g.
Budget sources of protein
The most expensive sources of protein are seafood, fish and meat. They will have to buy less often. What to take for a replacement? For example, beans. Chickpeas, lentils, and beans are high in protein and choline.

Stock up on inexpensive canned beans or boil them yourself. Add cooked beans and lentils to salads, soups, and stews, or mix with rice and buckwheat for a more nutritious side dish.

Chickpeas are great for homemade hummus or a healthy dessert like brownies or cookies. And don't throw away aquafaba, the liquid from cooking beans: use it instead of egg whites for baking and sauces.

Budget Sources of Fiber and Vitamins
These substances are found in vegetables and fruits. In the warm season, zucchini, tomatoes and peaches are sold at reasonable prices, but in winter many people cannot afford it. To save money, shop for seasonal items. In the cold months, these are different types of cabbage, carrots, turnips, radishes, beets, persimmons, apples, pears, quinces and citrus fruits.
How to create a healthy and inexpensive menu
I hope I didn't help you much.
I wish you a nice day and good mood. Veronica