I've been making stock as far back as I can remember. My mom made stock a few times a year. The most memorable time being Thanksgiving evening. After dinner, while cleaning up the kitchen she would pull out her big stock pot and put in all of the turkey bones along with some onion, celery, and carrots. I remember waking up the next morning to the delicious smell of turkey stock on the stove. She'd normally freeze a lot of it, but she'd also take leftover turkey and make turkey noodle soup. My Mom is a fabulous cook. She's where I learned to cook, and where I get my passion for cooking from.
You can't beat the depth of flavor in homemade stock, especially when added to a delicious homemade soup. It's also super nutritious, the collagen from the bones has immunity-boosting power! Store bought stock is usually salt-laden and full of MSG. You're also saving money by making your own. If you are already eating bone-in chicken, you're stretching your purchase even farther by making stock too. Here's a tip: If you're only having a few bone-in pieces of chicken, or you would like to save a whole bunch of bones for one big batch of stock, just throw them into a freezer bag until you're ready to make it. I also save pieces of vegetables in the freezer as well, like the green parts of leeks, celery tops/leaves or celery/carrots that are limp.
If you've never made stock, you will be shocked when you see how easy it is. You literally throw everything in the pot and walk away, for a minimum of 4 hours. Then you strain it, let it cool and do with it what you'd like! I freeze mine in 2 cup portions for easier measuring later on when I'm cooking. A great thing about making this stock is that you can just use what you have. If you don't have something that the recipe calls for, no big deal! Make it anyway. My mom has made stock before with nothing but the bones, and it's still delicious. The recipe I'm giving is for just 1 chicken carcass (sorry, there's no "prettier" version of the word). If you've got more than one, just double or triple the recipe to suit your needs.
Bones of an entire chicken
1 large onion, peel off the outer skin then cut in half
2 carrots, scrubbed and chopped in half (if not organic, peel first)
2 celery stalks with leaves, chopped in half
Hand full of fresh parsley, stems included (you can sub dried parsley, maybe 1-2 T)
1 head of garlic, unpeeled and cut in half crosswise
Put everything into a large pot, add enough water to cover everything by about half an inch. Bring to a boil, then put the lid on and turn down to a low simmer for at least four hours. I usually make mine at night, and let it simmer on low overnight.
Strain over a colander and discard the solids. You can stop here, but I like to strain mine again over a coffee filter, paper towels or cheesecloth. Let it cool, then freeze! It should last in the freezer for 3 months.
I hope you try making your own stock, you probably won't go back to store bought once you've tried it. I'd love to hear about it if you make some, now go buy a whole chicken!