The key, fob, and programming is about $450. Allegedly there is (or was)one source that can program the key alone for the pre 07 chassis. The key itself has a non-powered chip that responds to a query by the switch. You can leave the FOB anywhere in the cab and use the key alone to start the engine.
A few 07 and later Sprinters are subject to a "no-start" problem. Several threads on the View/Navion forum on that problem. All of us that had the problem have speculations, but "the" fix has never been documented. Mine was fixed with a new key and fob.
