Connecting to a remote computer using the NoMachine Network service (by specifying the Machine Id) requires a Network Subscription. If you don't have a Network Subscription, you can still connect to a remote computer using its public or private IP address if you know it. This is free to do.

There are some services built on top of the NoMachine Network Infrastructure which are free to use without requiring a Network Subscription. 

- configure two-factor authentication to protect both logins with your User Id and remote connections to any of your computers. 2FA is freely available to all those with a NoMachine account (User Id) including users who opt to use the free version of NoMachine. Push notifications are received on your devices when there is a login or connection attempt. The app for iOS and Android is also free. You need a NoMachine account to be able to interact with 2FA.

- publish your computer on Network. Anyone can publish their machine on NoMachine Network. You don't need a subscription and you also don't need a NoMachine account to do that.