Yeah, LindaJane, my advice is to find a car in your area that you can drive and see, and have a good PPI (pre purchase inspection) done so that you know what you're getting into.
If you do find something on e-bay you like, why don't you ask someone on this forum if they're in the area where the car is sold, and see if they'll look at the car and get it inspected for you?
I live in Southern California, and there are tons of MB Diesels available here.
If you see an MB diesel on E-bay that is in Southern California, I'd be glad to go look at it for you, and have it inspected by a competent MB independent shop.
Oh, and another thing. By all means, buy a car with as many records, and in the best condition possible.
Learn from my experience and others on this site. It is always cheaper to pay a high price for a clean, well-maintained car, than to buy a questionable car for a cheap price, and then try and bring it back to life.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".