Well, "worth" is a relative term. Tobias clearly thinks they perform exceptionally well, so they're worth $30 each to him. But others may look at them and think of a much smaller number. On the flip side, there will always be the people that have convinced themselves that they've found the playing card equivalent of a flawless diamond and will throw obscene amounts of currency at the sellers. It's one of those situations where it all depends on who sees the item for sale. "Old" items like these heavily rely on the public perception of their own value.