So someone was swindled into paying money for a link to the free sourceforge download - yup, that's definitely a scam all right...
Something tells me someone was probably going to pull something like this with something free sooner or later, seems everyone wants to make a buck these days, even if it's through illegal means.
Well, being that the seller is based in the U.S. I'd say there is more than enough grounds to prosecute, although I'm not a lawyer.
I would suggest one of the devs, if they wish to pursue this, be chosen to represent the collective developers and contributers to this project and go through the VERO program on ebay - the form did state explicitly that it would not have to be filled out and submitted by the actual creator(s) of the work, but could be done by someone authorized to represent.
Simply going through the VERO program alone might be enough to stop this scandal, and would not necessarily mean a drawn-out legal battle, therefore I would suggest the VERO form first.