One that hasn't gone off.... Doesn't matter what kind of car.
You might be able to find one on Craigslist, Kijiji, or Freecycle. Also, you can look in your local papers for ads...perhaps someone has one they don't need.
Other than that, there really isn't anything else that I know of unless you just ask around (friends, family, etc...) and see if anyone has one, or knows someone that might have one...or visit your local junk yard. :/
Junk yards would be your best bet. They have junk yards where if you pull it yourself, its free. Just call the ones in your local area and ask around.