Owning any Mercedes can get to be expensive as time goes on, especially one that comes with a history of poor maintenance. The more hands the car passes through the greater the probablility it was abused. But even a well maintained car can need a new parts, especially ones that are subject to wear during operation or are sensitive to the effects of aging, like plastics and rubber.
I joined the Mercedes-Benz Club of America to get the discounts on labor and parts from the local dealer. I have a couple of old cars that, even with a one or two owner history and good attention to maintenance, need a little refreshing on a regular basis. I have also learned to enjoy exploring the limits of durability with these cars, which my wife sometimes thinks is a mental disorder. I have also learned to do much of the work that requires no more than pretty standard tools myself.
As for the MBCA, the discounts are definitely worth the price of admission. I get up to 20% off most parts and 10 to 15% off most labor. On your $250 valve that covers more than the tax! Doing the work your self also saves a chunk of change.
Owning these cars on a regular income is part of the common theme on this and the Diesel car forum. It requires taking a little bit of a risk with a car that has had one or more previous owners. This forum offers ways to learn about any prospective buys to help reduce the risks of buying a lemon, and there are lots of people with lots of personal experience to help you through the selection process. I only wish I had known of such a resource when I bought my 350SD in 1995.
But the reward for taking that risk is driving a vehicle steeped with the safety features as Christian noted above, and the ride and handling others have noted. Successfully managing that risk allows you to own an expensive car without being part of the upper crust of the social structure or suffering the expenses they pay to own these cars. Jim
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)