Microsoft Azure has a REAIS price list here in Brazil.
But when you charge your card (if that's your payment method) you will get the value in REAL, and convert it to DOLLARS in the change of day.
This is because, the Brazilian Central Bank, does not allow foreign companies to charge in national currency.
Example:
Your account gave $ 50 at the end of a month.
The dollar on the credit day on the card was at $ 3.2510.
Microsoft will charge your card 50.00 / 3.2510 = $ 15.38
There, your credit card operator will do the opposite, but on the bill's due date:
Microsoft charged you $ 15.38
The dollar on the bill's due date was R $ 3.2865
The card operator will charge you 15.38 x 3.2865 = R $ 50.55.
Now, the government is drooling and splintering a tax called IOF (Tax on Financial Transactions) in the amount of 6.38%, and charges you in the same invoice R $ 55.55 * 0.0638 = R $ 3, 23
In the end, a service that Microsoft has charged you $ 50, because of Banco Centra and the taxes of our government, you will pay R $ 53.78
Simple, right? :)
= > In the end, Microsoft will charge you in DOLLARS.