Houses used to stack when some of us got our pledges. So many players tried to keep their complete set perhaps but now maybe they decide to get rid of them. I am a hoarder a little and have all of mine still but maybe one day I will sell some. I originally chose to start the game for like the $90 pledge but then I increased that over time and the houses from each tier stayed with me. I don't think it means anything players are selling them. There is no way to know exactly how much things are worth in this game. It is a players game and they control the prices. The best way to figure out how much you would like to sell things for is just to play the game and check vendors here and there to get ideas. Items do have a value on them which does give a hint if you look. Like an artifact will have a larger value than most things. So the value you see in your inventory for each item doesn't mean players have to sell it for that. It is kind of a guessing game. When I price items to sell I guess. I don't try to undercut but since I don't micromanage it or am not constantly watching prices even though I do visit owlshead and look at vendors occasionally. I just guess mostly.