I was searching for the external BT antenna for my G5 powermac and almost every place had it for around $29 + shipping. There is/was 1 on ebay and it was at $36 last time i checked it. However i found an online retailer (FastMac) that has it for $12.95 +shipping so i bought one for about $20 shipped. Here is a link if anyone else is interest.
http://store.fastmac.com/product_info.php?cPath=9_16&products_id=36
http://store.fastmac.com/product_info.php?cPath=9_16&products_id=36