I've just put up two N64 GameShark Pros for sale on eBay. They're brand new, never opened, version 3.2's. Starting bid is only $5, Buy it Now price is only $15. One is a three day auction, the other is a five day.
http://members.ebay.com/aboutme/cdidesign/
http://members.ebay.com/aboutme/cdidesign/