Service records would be nice, a properly maintained Mercedes can do high mileage; a pre-purchase inspection by a Mercedes familiar shop would be great. Being alerted to issues like low compression, fault codes, rotting suspension joints are factors to consider with the price. Fairly high mileage for a car driven by "an old lady" but who knows. On the other hand, if you're only looking for the car to last a few years, the price could be right.