I think that there should be a formal market where one could place a card to be sold and others could bid on it. This would be used instead of the informal market in the forum. This could allow for a more organized way to find cards and it would allow for a longer bidding time on cards. If it were more formal, then at the end of the bidding time the card and credits could be exchanged automatically and there would be no need to be online when the bidding was over. This would also allow for a better pricing for retired cards.