And is it like the normal Game Pass?
For what? At Microsoft you get 3 months Ultimate Game Pass for 1 euro - cheaper would only be free.
Yes you can, you will then receive a code that you can redeem in the xbox store
Yes you can
No, you have to log in with your Xbox account to buy it, then it will be automatically credited to you.
No? If you buy it via the xBox, then yes, but you can also buy a prepaid card
I can only pay with paysafecard and you can't do that in the Microsoft store
You can, but there's no 1 euro offer.
Yes