Dealer only if your looking for a OEM look, Call your Local Salvage yard and see what they have and do a locate. The other thing you can do is just give them a wish list and have them call you when a Envoy ends up in there yard.
I know a guy on kitchener Waterloo area he said around 500 to me to get one though his shop discount. Personally I'd do what the other guy said find one clean it up and paint it be a lot cheaper then buying one and still having to paint it.