DHTML Menu Studio costs $49.00 per license (Standard Edition) or $99.00 (Professional Edition) but comes free with Xtreeme SiteXpert -- a complete web site navigation solution. You can find out more at http://www.xtreeme.com/dhtml/

The only difference between the demo and full version is that the demo will strip all links from menu items.

You can purchase DHTML Menu Studio here

You can purchase Xtreeme SiteXpert (with a free copy of DHTML Menu Studio included) here