Ebay or Craig's list probably. 
I bougt this used with 100K miles on it two years ago. I didn't check it out adequately. One of the three cyclinders didn't keep compression. Now, after putting on 12K miles, engine is shot, so decided to sell it. What's best way? It's in KC metro area at Mercedes dealer. No dents in body, just needs working engine. Clean overall. have clean title. Suggestions?