If i find an iphone can i sell it?

If i find an iphone can i sell it?

Why don't you try to return it?

It likely has a bad ESN, if someone reported it lost or stolen.

Not legally. It isn't yours. As soon as it is reported as stolen or lost, it will be blacklisted from obtaining cellular & data service. A cynic might think that someone asking your question in that manner was actually PLANNING to "find" one.