Avoid old luxury cars. Your budget will get you an S-Class that's over 15 years old. These will be worn out and in need of significant money and maintenance to keep them on the road. I think you'd be buying into a whole heap of trouble. You'd be better off with something newer and more affordable. The Honda Jazz 1.3 CVT automatic petrol would be my recommendation. It's reliable, comfortable and has a raised driving position that will make access easy.