More like an elaborate lottery ticket. Or a digital record about being the rightful owners of part of "Project G484" or other. Basically until someone had all the pieces, not even the real contents would be shown. There is a legal "piramid game" going on, if enough people buy parts of unfinished ships, the finished ones would be given out depending on the "lucky draw", and of course new owners could, and should be trading their deeds, or selling them, or putting them on auction... all of it helping make a little more money to help clean out the unfnished businness around the sector - or more.
So, the 'deed' has no price for it, the prince just hoped to get something for it with the same price range - and lost it.