Premium members can create a second premium account for free.
To create a second account, log in by going to:
https://unseen.is and on the top right of your unseen page next to your coin will be a gear/settings button.
Hover your cursor over the gear/settings icon and choose "Account management"
Click on "Create Account"
Fill in the info. needed and choose Premium for the account type.
Click "Create" when you're done and you should have a second free premium account shown in your account management.