K-mart, Walmart, Radio Shack, Crutchfield, pep-Boys, or just about any other auto parts chain will carry the wiring harness for the Contours. I ordered my Kenwood from Crutchfield and got it for free. That way if you ever get rid of the car you can pull your after-market head unit out and reinsert the stock one in about 5 minutes.
...and that price is about right, it should cost around $10.00 I'm not sure what year you have, but mine is a 99 SE without Premium Sound. If you have the Premium Sound package, It'll say on the speaker grills located on the doors.
Hope that helps.
