There really isn't any reason we should be running to the store and grabbing boxes of chicken oxo cubes, or cans/boxes of chicken stock.
1. It is expensive
2. It is full of added ingredients you should really limit! (msg, SALT, for some well-known products see here for their list of ingredients)
Making home made stock couldn't be easier:
1. Save chicken bones from any whole you chickens you consume (even rotisserie from the store)
2. Save chicken bones from any meal that features bone-in chicken
3. Save carrot peels, tops and ends, celery ends (if you like celery)
4. Keep a ziplock bag in your freezer for leftover carrot peels, bits of onions and celery
5. Keep another bag in the freezer to collect any chicken bones
When I have accumulated about 2 cups of bones and 2 cups of peelings and vegetable bits, I combine everything in my slow-cooker and cook it overnight on low, or for at least 12 hours.
Re-Use Those Bones!
Cook those things until they're crumbling between your fingers. But be sure to use cheesecloth or a nut-bag or something similar to strain your cooled stock. In re-using the bones, your second and third batches won't be as rich, however there's plenty of vitamins and minerals left to make it worth it! This ("twice over") broth can be used to cook rice, boil pasta with, or in other dishes where the stock isn't the main feature.
For a great frugal bone-broth resource see the Nourishing Gourmet
Storing Your Stock:
You can keep the stock in the fridge for up to 5 days, and if you don't use it before then, just bring it to a boil again and it's safe to store for an additional five.