As my main NPC deals in everything that can be found, inlcuding any artifacts he can get his hands on (he's the leader of the most prosperous guild in the planes), I've had exp with this before and can honestly say this: with the danger of procuring the egg, the magical costs to keep the egg a live egg until it's sold, dealing with the political issues (paying off nobels to keep the egg and keep outta trouble), traps and guards to keep such valuable merchandise from being stolen, transportation, possible religious issues in the area, the fact that it could be considered slavery, the fact that a signle dragon is enough to desimate an entire empire, blah blah blah...  A dragon egg is reasonably worth more than 1.5 mill gp, modified certain above factors and the type of dragon of course.  Unless someone in the country runs a dragon farm, a draconic companion (other than faerie dracs and drac turtles(included here for the benefit of my players who insist a dragon turtle is a dragon)) or the like are out of reach for unless the pcs are high lvl (practically epic) or come from families to whom 100's of 1,000's of gold are like pocket change.