One thing you could try is approaching the US Postal Service. If part of the deal was conducted using the USPS, you may be entitled to pursue this as a form of mail fraud.
Of course, with you as a resident of another country, there may not be any recourse within US laws. You should look at any recourse within UK laws, although the best they could do is possibly prevent the person from conducting business in the UK in the future.
I guess you could sue the person in the court of jurisdiction where they live, but the cost of the litigation and representing yourself or having someone else represent you (even in small claims court) would probably exceed the moneys you could recover. And if they really don't have the money, how do you intend to force them to give it back?
To be honest, I think you got ripped off and you have to write it off to experience.
There is an online board of inquiry site that allows you to post specifics of a case such as this so that others don't fall into the same trap. I can't give the URL here on KS.com because it will get bleeped out, but if you do a google search, you should be able to find it.
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Chris Harrison