There are a number of cars for sale around the country.
The most comprehensive resource for these cars on the Internet is at
www.500e.com which has great archives and information specializing in these cars.
The 500E is a great all-around performance car that more than holds its own against 90% of today's cars, even the so-called "AMG" models. It has less electronics and modularity, and higher build quality, than today's cars.
More importantly, though, is that it's a practical performance car. It isn't particularly demanding to maintain, though moreso than a run-of-the-mill 124. The value and bang for the buck are quite high. Many many owners of newer "AMG E55" E-class successors who have owned the 500E in the past, will tell you that they prefer the older car, and either intend or have already purchased another 500E after selling their E55.
Best advice is to go to the mecca for these cars, and that is
www.500e.com
This site's threads on the topic are also quite a gold-mine and are probably even better suited for the POTENTIAL buyer.
www.500E.com is more suited for the CURRENT OWNER.
Cheers,
Gerry