It is only available in City Folk and is only useful at GracieGrace and the Auction House, because the prices can be extremely high and only 99,999 Bells can be carried at a time. The player may only get the Shopping Card by depositing over 10,000 Bells into the Automatic Bell Dispenser (ABD). A letter will be received with the shopping card attached the next day. However, since it won't work at Tom Nooks, nobody can use it there.