I was on Facebook and I have Mercedes as a like, well off to the side I saw a link for MB Service USA credit for 2006 or older models, I filled out the info and MB USA emailed me a $50 gift card, it has a pin number too, that I can use toward a service. Just watch the expire date, mine is 7/20/11
My certificate was for $50, for my c240
Just as an fyi, I did post this in my model specific forum, and many of us have received the certificates, seems as though if you enter a 2001 slk it will pop out a $100 cert, the cert itself does not show a model, year or anything.
Some dealership may hassle you and they may say service only, but the cert states "parts, labor and accessories" if you battle you will get it.
Before I knew about the 2001 slk, I had a $25 cert to use and got 2 oil filters and the engine fuel system cleaner, from one dealer paid $7, then today I got rear pads, 2 sensors and 2 fuel system cleaners fro another dealer, paid $24.
In case you want to read the other threads here are the links...
Here is the link