When will expire and how you know? Even You are in poland and have a Polish account you can activete it on your account. And after you change your console region in the settings to USA, you can spend the 5 Dollars.Hi!
I have $5 xbox code (you probably know that already). I recived it from microsoft, and it will expire in two weeks. I live in Poland, so I can't redeem it. I will trade it for some other xbox code (game, trial etc.)
(My english could be awful, sorry)