clarencestone

Does anyone know a way (other than thru the dealership) that I can purchase a new key fob and have it programmed for the car? 2005 SL55 I understand I cannot purchase a used one because the eprom in the keys get "flashed" to the vehicle on a one time basis. But I have seen new keys on line (not from the dealership) and I am wondering if they are worth the trouble. My mechanic says he can do the programming but only if the key is purchased through the dealership. Thanks,