Brian constructed his organ in stages, with an initial cost of only $66. His workstation has come a long way! The costs associated with each phase are documented on the Hauptwerk Organ Plan page of his website. Of particular interest is how the organ has been built into the small alcove in his home - the custom desk is quite nice.
Brian runs the midiorgan.com website, which is a great resource for anyone looking to assemble a home, hobby or practice organ.