For €2.50 per month you use the badge in Italy, you will no longer have to queue at the Italian tolls! You only pay for the Italy extension during months when you use your badge in Italy. It is free for the rest of the year.
The same goes for usage fees in France: €1.70 for the months you use your badge in France, €0 for the months you don’t. There are so many good reasons to subscribe!