my whole car is down and the guy who is selling it to me told me its the relay

MB are mighty costly to maintain -- when you say "down" it sounds to be problem with airmatic system. car is almost 10yrs old and did i memtnion MB are mighty costly to maintain. In CA advertising new c-class lease @ $349 (their new C is a nice whip - but not an s)

Now think about that ...its just a relay. If it was just a relay why would he not have already put it in to sell the car easier......