Just Dance 2020 cost?

Moin, I got Just Dance 2020 for the Nintendo Switch today. In the box is a note with an unlimited 1-month voucher. Does that mean I have to pay extra in the game to play? And what is meant by the unlimited and do you need it? I paid the full price and would find it unacceptable if you had to pay extra to play because the game itself is not cheap.

So the 1 month unlimited voucher is there to play more songs in Just dance