The mileage really does not matter. It's the fact that you have no service history on the car.
I have a 124 with 290K on and everything works well. However I knew all of the service history on the car before I bought it 4.5 years ago (190K).
I looked at a 300E a year ago with over 300K on the clock full service records. The original owner was an anal accountant and had taken excellent care of the car...He decided he was too attached to the car to sell it to me. I would have bought it otherwise.....
If your going to buy an inexpensive benz make sure it's one that you have all the serivice history on. Good luck !