While its versatility cannot be ignored, chicken stock is not an expensive endeavor at all. All you are using are really mostly scraps collected from your daily cooking. Here're what you need:
1 -2 lbs. of chicken bones (washed, fat removed)
Carrots, Celery, Onions (25%, 25%, 50% respectively)
2 sprigs of thyme
2 bay leaves (dried or fresh)
1 bunch parsley stems
1 teaspoon peppercorns (optional)
Chicken bones can be obtained when you remove the chicken meat from the bones during cooking. Wash the bones thoroughly to remove most of the blood and fat, which serves no purpose at all but produce a dirty byproduct (also known as scum) that must eventually be scooped off anyway. As you slowly accumulate these bones, you can store them in your freezer until you have enough to make your stock.
The combination of carrots, celery and onions is known as mirepoix in culinary circles. It is used most often for making stocks and braising meats and serves the purpose of providing even more body to a liquid already deeply flavored by the bones. To keep cost down, I supplement the mirepoix with scraps from the three vegetables produced in the course of my daily cooking. These scraps include carrot skins and the ends of carrots, onions and celery that would otherwise be discarded. There is nothing fundamentally wrong with using these throwaway parts in making stocks because they would be eventually thrown away anyway after all the flavors have been extracted from them. Just make sure you wash them first to remove any grit or dirt. Also, in place of onions, you can even use the white-colored root ends of scallions.
Getting the stock started is as easy as placing all the above ingredients in a stock pot and filling it up with cold water. The amount of water should be enough to just immerse everything. Too much water and the stock will be too thin. Turn on the heat and let it come to a slow simmer. Do not stir the ingredients while the pot is simmering as this will disperse the scum that usually accumulates at the surface. Every thirty minutes or so, use a spoon to remove the scum. Continue simmering the pot for about 2 - 3 hours (depending on how big a pot you are making) and the chicken stock should be ready. All you need to do now is to strain the liquid from the solids. Let the stock cool down to room temperature before storing it. Chicken stock can be stored for about 1 - 2 weeks in the refrigerator or up to a month in the freezer.
Be careful not to over-reduce the stock. Believe it or not, contrary to popular belief, some flavor is lost when chicken stock is over-reduced. If you need to reinforce the stock, make another batch of chicken stock using existing chicken stock in addition to water.
Now you can enjoy homemade chicken stock in your everyday cooking!