You can actually make stock for free, or close to free. Just keep the vegetable and chicken trimmings you accumulate thru the year in a bag or container in the freezer.
Note: The following will fit into a 12-quart stock pot. You can double or triple the recipe for a larger stockpot.
3-4poundschickencut into pieces, rinsed (Note: I also save the tips when I make chicken wings. Freeze them and throw them into the pot when making stock)