Are you getting an error message saying that you are not in an eligible region to install Spotify or another skill you want?
Follow these steps:
Change your Amazon account to another region:
Access Amazon.com:
Click on the menu: Your account: Account > Digital content and devices > Devices and Content.
Click on preferences: (to access skills in another region)
In settings - devices/region: Change your address to an address in another region where the skill is available, e.g. Brazil. Click on update.
Now just access the Amazon Alexa application, log out and log back in.
This process works for any skill that is not yet available in our country, but is available in others.
After you install the desired skills (Spotify and others), you can repeat the process and change your address back to Portugal. The already installed Skill will remain intact.
To install a Skill: (In this case, Spotify)
Open the Amazon Alexa application; On the bottom bar, click on More > Skills & Games > Search for Spotify > Enable to use.
Buy your Amazon Alexa here