if answer is yes, say he can do regular maintenance like spark plugs, oil, brake pads and fluid changes, you won't feel expensive, although parts could be around 30-50% higher.
if it's a no, well, under normal circustances, i.e. no major repairs, the cost of mercedes maintenance is about double than that of jap's cars - parts cost more and technician hourly rate is about 30% higher, and, the time to get job done is longer as it's more complicated requiring special tools in some cases. compounding all the factors, roughly about double is a reasonable estimate.
One thing to remember - you don't have to go to dealer for services; some mercedes specializing shops or so called "euro auto shops" do just as good as dealers. enjoy it.
