OIC...If his pedal has got an extension for the right/left pedal, then its no problem. If not, then there's no way he could just buy another pedal to make it a double pedal unless he's using two bass drum.
That's the standard price. If u were to get anything higher than within the range. Complain to CASE. Even Swee Lee's selling it between $420 to $460.. Just know how to bargain and which staff to approach..