I'd say about $45. I don't want to make it to low, since I know that the game maker might not make its investment otherwise, but a nice $15 discount, or some other incentive, might be enough to bring in people who are on the fence about purchasing it to give it a look anyway.
Unless they all decide to pirate it anyway, but there's just no reasoning with some people...
Unless they all decide to pirate it anyway, but there's just no reasoning with some people...