Are Apple iTunes gift cards considered money, thereby requiring parity when purchased in the same currency, and is it permissible for the seller to increase their price when selling them in a different currency?

iTunes cards are benefits and commodities, similar to phone cards, enabling their holder to access services from the producing company. It is permissible to sell them for their equivalent price, or more, or less, because they are not currency nor are they treated as such. Therefore, equality and immediate exchange are not conditions for their sale.