Price doesn't matter, people buy shitty Apple overpriced IPad's for 800, so why couldn't motion controler sell for 150? I wouldn't buy it (but not because of the price), but that doesn't mean there isn't a market for it, rabid fanboys and people falling for the cool factor will get it and there is a billion of them.
MY HYPE LIST: 1) Gran Turismo 5; 2) Civilization V; 3) Starcraft II; 4) The Last Guardian; 5) Metal Gear Solid: Rising