Probably the same button that used to be in shops. As of yet there are no codes for free stuff in Pirates. However, it has been used in the past, I think, for the Kracken tattoo from the Call of the Kraken game. It may also be that they are reserving the right to add codes in at a later date, as both Cars and Pixie Hollow have codes for free items at the moment. Then again, this is D, and it could just be nothing.
