well - you actually cant buy a ghosthawk in game, you can only get them from doing a blackwater and even then its 'supposedly' a 1% chance of getting, which makes them incredibly rare and dangerous if you have one. So, the market dictates the price of these items, since there aren't many of them out there and a lot of people want to buy them...they will priced high...if someone pays 50mil for a ghosthawk (which apparently someone did) then anyone else selling is going to want that type of money...