You can choose to use Brezzels in Euro or US Dollar from the user menu on Brezzels. By default, Brezzels will preset a currency for you. You will see all prices in the currency you have set, which you can then use for the transaction. The debit from your specified payment method will also be in the currency you set during the purchase process. You can change your currency at any time, but not retroactively for payments already made or for current subscriptions.