How much is the average fees for maintaince

What is your question?

I am going to buy a Mercedes-Benz C300 - 2008 - 54 000. I am still debating over to buy this car or BMW 2008 328i or Genesis 2011 Hyundai. I am extremely clueless about car, so I just want to know which one I should get and pros, cons. It would be extremely useful if anyone can provide in details common damages or broken parts of each car, and expenses to fix it.