That sems crazy high considering you can get the Holden ones*(set of 4) for $200ish shipped for a set for Assie Land. Maybe check out JHP?
You could also search some forums. You can get a whole set of used 17s for a few $100 worst case. Also call Cleveland Pick-A-Part or fParts to see if they have any.
$30 each on eBay - http://www.ebay.com/itm/ONE-04-06-Po...53dab9&vxp=mtr
2003 Corvette Z06 - MGW shifter, Corsa X pipe, Corsa Xtreme exhaust, PowerStop rotors/pads, Conti DWS tires, C6Z51 F&R sways, Depo C5R headlights(not installed yet)
04 GTO - sold