How can I buy high end Mercedes Benz?

Find one coming off a three year lease. You can pick up one for $20,000 to $30,000 less than new and it still has a two year warranty.

I wouldn't suggest buying even an old used one, because maintenance costs on German luxury cars is expensive, and you may not know how well the car was taken care of.

I'd recommend an Acura or a Lexus of that age. You probably could find a good deal on one, and due to it being a luxury Honda or Toyota, it would be very reliable.

How about buying a second-hand one if you don't have enough money for a brand new car.

You will need lots of money.

If you can't afford it, you can't buy it.

You not be able buying high end Mercedes Benz if you need more money while can't afford it.

I be owning one and maintannce be very high, and I be able afford it.

First of all, you need enough money. Then you go to the dealership and purchase one.

Buy a really old beat up one. 

I guess steal or else wait for your reincarnation and hope you get born as a rich person in next life

Get a better job.