Well the last used copy of the Trilogy Box Set went for over US $150. So this one should fetch a good price.
http://www.ebay.com/itm/Marathon-Trilogy-Box-Set-for-Mac-OS-macintosh-bungie-pathways-into-darkness-/290856650258?pt=Video_Games_Games&hash=item43b8684612
All the contents is there including the elusive Trilogy stickers and the super rare Marathon Scrapbook... the concise version of Bungie's early history. Error strewn for added authenticity.
Have you got your copy? Don't settle for the meek revisionist version. :)
Cheers
Hamish