You can make your own stock from the carcasses of the whole chickens, it’s a bit time-consuming but very easy and much healthier. Boil up 2 or 3 in a big stockpot for a few hours with a couple onions, some celery & carrots (even cheaper — use veggie scraps & peelings — throw & freeze them in a big ziplock until it’s full) and some herbs & pepper. You control the salt, I don’t add much at all. Strain & freeze in small batches you can defrost easily or in ice cube trays (just grab 3 or 4 whenever you need a little for a recipe).
I do this. I don’t can due to inability to lift the canner and having a glass top stove. Right now I am overloaded with carcasses and need to find a day to make stock. I save all veggie scraps and the liquid from canned veggies for this, too. No need for much salt at all as the canned liquid is salty. I much prefer my own. I agree about freezing in ziplocks. I place them on a cookie sheet until they are solid and then stack them in the freezer. The ice cubes just go into small zips.
I try to keep canned stock around in case of power outages that would impact the freezers. I have taken the advice of FReepers and cut off the wings of whole chickens, add them to the wings found in family packs and then don’t have to pay $2+/lb for wings. I also freeze skin and the fat from whole birds and make my own rendered chicken fat and cracklings (gribbens). Interestingly, I was searching Asian food blogs and discovered Vietnamese and Chinese cooks also render chicken fat and make chicken skin cracklings. One blogger described just draping the skin over a rack in the oven while also baking a chicken dish and catching the drippings in a pan. The racked skin becomes crisp and can be used like cracklings. I remember that one of our FReeper cooks also makes her rendered fat and cracklings in the oven.