What about making black market based off of both how many bought total and personal. What about this for the formula. (Original cost based of difficulty)*(number bought personally)^(1+(. number of total bm items bought globally). That way everyone gets the first of each type for cheap and then goes up exponentially. This would also limit the first claim snowball effect that we see now. This is a good come from behind type change as those who have used the bm until endgame can punish the leaders as it is still (realitivly) cheap.