I believe that it's unethical. It's not as if this shortage all of a sudden cropped up. He knew how many he had to sell from day one, and that there would be no more. It's certainly not illegal, though. Note that I have no interest in buying another unit, regardless of his or anyone else's prices. But with that attitude, I know I won't ever be buying anything from him, either. That doesn't mean you can't.