Welcome to AF!!
Let's see... I got my passenger side mirror off a 4-door (which doesn't fit perfect), and I paid about $20. My buddy just got a mirror off a hatch (for his hatch) for about the same price.
Personally, I'd just surf the 'net for a stock passenger mirror. The only aftermarket mirrors that I've seen worth buying are about $300.
Try
http://www.partsadventure.com
I got my dash clock & GSR console from them. They have all kinds of 4g parts for decent prices.