Further update after a week there - if there are buoys use them. If not, in all but 'MA' areas (which are prohibited to all entry), you can anchor
. Buy the permit online as it's much cheaper and be ready to show the police.
Cala Nord off Budelli was packed in the day and magic at night. Cala Garibaldi was lovely (the Club Med is closed), Porto Palma was ok and Villmarina was also lovely. If you stay out of La Maddalena itself and provision in advnace, there is nothing to spend your money
on and it's actually very cheap!