you are comparing apples to thakay howay oranges here. A mercedes benz (even a small C class) is far more refined than your average toyota camry. I would suggest that being Pakistan where the only dealer is not very freindly and most benz' are imported secondhand from UK hence have their special quirks, do not buy a first year car, meaning if you want to buy a W203 do not buy its first year of production - it would have problems - normally MB would have repaired them free of charge but being Pakistan the problems can or cannot be solved depending on the car you get.
There is no voodoo or spaceship rocket science in owning a benz, its parts cost the same as any car of similar caliber and when its worked on it can be brought back to 100% service spec everytime. Thats why its the choice name for police squad cars and taxis all across European countries.
Do not just go for the head turning, bling bling factor, Its real joy is in driving it, I have a 17 year old mercedes and a nearly brand new Nissan Altima and had a 2011 camry too for a few months. I always prefer my benz, it can take the road like no other. New jap medium sized sedans feel like "juicers and blenders" compared to it. - My wife on the other hand does not like the weighted steering, heavy doors that close with a vault like thud or its extremely plain A/C controls set in real zebra wood.
While owning this benz I have spent about USD 600/- in repairs (parts only as labour is free for me) in a year - pretty acceptable to keep it in worth quality. People average about USD 1000 - 1500/year be it new or old to keep a mercedes benz in good quality running. I have had exactly similar experiences in owning a similar age Toyota Camry.