RE: What kind of starter?
With very few exceptions, all my soups start from scratch. I make stock out of anything and everything I can find. I currently have about three quarts of chicken stock, and two quarts each of veal, clam and lobster stock in my freezer.
I control the fat, I control the salt, I forget whatever it was I seasoned it with, so its always a crapshoot as what it tastes like when I thaw it, but that just adds to the fun.