In short: It's a rare color, and it's very difficult to produce unlike common red or green pens (or the common 1W blues, this here is a different shade of blue).
I think a few years ago this would've sold in an instant, however with the availability of cheaper higher powered 473's, there's a lack of interest... I personally would like a pen sized 473 but I need to settle some debts before I consider spending again. Either way, I need to list more stuff on the popular auction site that likes to steal your money and send it to some other place that steals more of your money... plus I want to start building lasers.
Good luck man,
-Z
But you just did! It doesn't seem like anybody else has much interest in it, just try to save up! I guarantee you that 473nm is a very nice color, having owned 4 of them :na: