I sold a 2002 C class a year back. The owner replaced front shocks and brake discs once. It costed him around 50k as far as i remember. The shocks were brand new and original. No copies. Same goes for brake discs.
He drives the car real hard and the car is often on Kohat-RWP-LHR route.
I have heard the Kohat road is not in a good condition.
So far, he is happy and the car has not asked for any other maintenance.
It is always very important to buy a car which has a maintenance history. This becomes more important when buying a high technology car. Benz and BMW MUST only be bought when their history is available. It is not necessary that they must be shahnawaz maintained but at least some info must be available.
A good clean car wont ask for maintenance except oil and filter change and that too after minimum 10k km.
As @xulfiqar says, there is nothing more expensive than buying a cheap mercedes. 
