When you buy a Skype product (like a prepaid card or voucher) in a retail store or through a third-party vendor, you are charged in the local currency.
However, in your Skype account, you can only choose a limited number of currencies to buy Skype products with (you can find out which currencies Skype supports here). If we don't support the currency you purchased your Skype product with, we’ll simply convert the value of your card or other purchase to a usable currency. This happens when you redeem the item in your Skype account.
Learn more about purchasing and redeeming Skype prepaid cards.