Nintendo account cost?

I'm a real noob when it comes to consoles and video games xD So I wanted to ask a few things about the Nintendo Account and think before I get the switch.

I read and also heard that you have to pay monthly for the Nintendo Account. Is that correct? So of course if you want to buy something from the e shop you have to pay, but if you don't want to play online (only with a card, for example) or want to buy something from the e shop, you have to pay for the account yourself or it's free? I would find it rather strange if you have to pay for an account, but I still ask to be sure.
if you want to play on the switch multiplayer (eg mariokart), it doesn't cost anything, does it? Since a friend told me that it is no longer free but I think she meant playing online?

Please do not have me asking (of course) questions that I take for granted. I don't really know anything about that

I thank you already times in advance

LG Viki

ps. Sorry for my spelling and grammatical errors.

You only have to pay for online mode, the account itself and the local multiplayer is free.

You only have to pay something if you want to play online with others.

E-shop and local mode should work without a subscription.

The Nintendo Account does not cost you anything to create and use, the only thing that would cost you would be a Nintendo Membership which is very cheap for 20 euro a year.

You can play locally with every game without this membership and online only with MIT.