When the budget is tight, and when is it not, it’s worked for me to plan a minimum number of servings of the most expensive part of the meal or the main dish, and then have enough side dishes or a decent amount of an inexpensive filler on the side for everybody to use to fill in the hollow spots. This way, so nobody leaves hungry, but neither are they filling themselves to the gills with the highest priced items on the table. In addition to the usual basic rice, noodles, bread, and mashed potatoes, you could try stuff like:
side dishes of seasonal fruit or vegetables
Make a first course of soup to take the edge off.
Fan-cut baked potatoes
Caraway seed bread (both a soaked grain and a regular version)
Roasted winter vegetables (if you have leftovers of this, they go nicely in a pot pie or in soup the following day)
Make your own batch of biscuit mix and you can set out extra biscuits (or cheesey biscuits) in a jiffy.
Irish Soda Bread (including a soaked grains version)
Basic whole wheat bread
We also sometimes just serve popcorn (made from scratch, not the microwave kind) as a side-dish for meals where chips would more traditionally be served.