The only one I could find recently on ebay went for 90 bucks
http://cgi.ebay.com/Guillow-304-FI-156- ... 5199fee097
This was an early version of the kit mint in box - later versions of this kit delete the swastika from the box art. 90 bucks seem pretty high to me. 4 or so months ago the plan alone from that kit went for $5. The plan is really all you'd need to build the plane.
I just got the Puss Moth kit (also out of print, same series as the Storch) for 15 bucks or so with shipping. Box is a bit dingy, but kit is complete.
Its a crapshoot. Unless you cant wait...dont spend a huge amount.