Nothing is more frugal than making your own chicken broth out of totally free ingredients (most of which you would normally throw away). You can make it on the stove top, but I like to do mine in the slow cooker, cooking at least 12 hours and sometimes closer to 24 hours. You can also make two batches of broth from the same bones, but the second batch is weaker, so I don't usually bother. I also tend to have chicken carcasses accumulate in the freezer, so I just start a new batch.
It is simple as adding chicken bones (carcasses from a roasted or rotisserie chicken work great, as well as raw odds and ends) to water and cooking. After cooking, strain out the bones and bits of veggies. The basic broth is simply bones and water, but I also save carrot peelings, skins and ends of onions, celery that has passed its prime, etc., keeping them in a bag in the freezer until I start the broth. If you want to kick it up a notch, you can add chopped garlic or garlic powder, a bay leaf, and any other herbs or spices you like to use with chicken, and of course you can use fresh onion, carrots, celery, etc. If you add a splash of vinegar, it pulls more calcium out of the bones and you don't taste it at all. I like to roast the bones first, putting them in the oven and roasting until they turn a golden brown. This definitely adds a depth of flavor and color to the broth. Some people think it is gross, but I also sometimes buy raw chicken feet from the local Asian market - they are very nutritious and add natural gelatin to the broth. I usually do not add salt, choosing to add it to whatever final dish I use the broth for.
You can freeze the broth in ice cube trays, then move the cubes to a freezer bag, but I have a tendency to end up with multiple jars or freezer bags of broth taking up a disproportionate amount of room in my freezer, so I started condensing it down into my homemade chicken bouillon. It is so convenient to use - no need to defrost before using, and a gallon of broth condenses down into just over a cup or so.
The broth is wonderful as a base for soup, of course, but I also use it in place of some or all of the liquid when cooking rice, quinoa, pasta, dried beans, or making homemade Cream of Mushroom soup. If you are sick or having digestive issues, a simple cup of the broth by itself is very soothing and healing.