This one's in leather and priced about right:
http://cgi.ebay.com/ebaymotors/Porsche-996-Boxster-3-Spoke-Airbag-BRAND-NEW_W0QQcmdZViewItemQQ_trksidZp3286Q2em20Q2el1116Q QitemZ320283216240
Airbags for the 3 spoke wheels are spendy... lots of guys swap out the wheel for a new one or one with wood on it, but they keep their airbag.
Watching ebay is how I found mine. I paid $250 for a used vinyl one.