I can't use my currency because I live in P.R.

Puerto rico can't be used as a us state it's considered a different country

In order to use it you need to have a us military address

Puerto Rico is not a xbox live supported country so there's nothing anyone can do.

If xbox live is not supported in a country it's usually down to that countries laws or goverment

OK question does your account region match the currency of the card if not that would be why

Currency cards are region locked so if you have an Australian or Canadian account you can't use an us card

What happens is you cause split billing where you make a us sub account with the currency but you can't use it because your account region and biking info don't match the currency you would have to use the region migration tool under my account and change
my region

However if you don't physically live in the US you will have problems with major titles

Vicious,

This is because at the present time currency cannot be used to purchase a subscription with the exception of the Music Pass on Xbox One. This is stated in their

Currency FAQ:

Can I buy an Xbox Live Gold membership with the currency in my Microsoft account?

The currency in your Microsoft account can’t be used to buy an Xbox Live Gold membership at this time.

Can I buy music with the currency in my Microsoft account?

Beginning Holiday 2013, you will be able to use the currency in your Microsoft account to sign up for an Xbox Music Pass on Xbox One. Dates and availability of music for purchase varies by device and region.

The wording "at this time" makes we wonder if they will allow it in the future though, but as it stands now this is why you can't use the currency to purchase the subscription.

You can't use currency in your account to by xbox live.

I think he means you can't purchase xbox gold membership with a gift card currency