Try looking for Herb-Ox Low Sodium chicken broth...
Herb-Ox makes a number of different broths, chicken, beef, and vegetable. Some are high sodium but they also do a lone of low-sodium too, in either powder or boullion cubes.
I've been using the beef and chicken broths a lot and they're pretty decent. I even do my own version of Ramen Noodles using the low sodium broths and some other spices, tossing out the package of spice provided with the noodles.
If you're really bold and have the time, make it yourself!
In a large pot with lots of water boil up a whole chicken (or chicken parts like 15 to twenty legs, breasts, wings, whatever, you can get either at a grocery store of course, try to remove as much fat as you can) with chopped celery, onion, garlic, ginger, parsley, carrots, bay leaves, peppercorns, whatever you prefer.
Boil for a few minutes then let it simmer for a few hours, just barely bubbling to reduce the amount of water. Skim off the fat and scum on the surface as it cools a bit and then strain out and save the liquid which can be used right away or frozen.
The longer you let things simmer the stronger the broth tends to get, though after a while you lose too much water and you have to watch that.
I've got some frozen broth made from the leftover cornish game hens I made up for Thanksgiving. I tossed in the leftovers plus some fresh veggies and a few other spices (I forgot what) and let that go for a while then froze the broth. It's good for a wonton soup I make, though I don't use it much, just for "special" occassions. The Herb-Ox broth is easier to use for something quick, I usually dissolve it per instructions in hot water.
Wylers makes low sodium broth powders too and there are some caned broths that you can find at
www.hearthealthymarket.com and in some specialty grocers....
By the way, I'm in the process of collecting exotic recipes for veggie broth, fish broth, and other interesting things.... I don't know WHAT I might use fish broth for, but I've seen it in a few different places and I think, as long as you're selective over what kinds of fish you use (watching the sodium counts in the fish) you can be pretty safe...