I bought one from the local dealer in Palm Springs. The price was $247. All I had to do was bring the car in so they could check the VIN . The key arrived about a week later. They went to the car and in a couple of minutes had it "tied" in to the car.
Do you have an indie that does work for you? If so, he might be able to call your local Mercedes and get his discounted price for you. That is how I got mine discounted.
Anziani
'97 CL600 56K