Just so you know, the US copyright law doesn't care if he is making money or not, all that matters is if he is violating any of the exclusive rights granted and reserved in the author of the work. His "profit" only matters if you sue him for money--realize that you can sue him to stop distributing your software, EVEN IF HE DOES SO FOR FREE.
I would contact the seller, ask him to stop, and also send him what is called a "cease and desist" letter. That usually works pretty well. If it does not, you will most likely need a lawyer.