The below tutorial shows how to create live classes with restricted paid access or classes which require your users to register in advance.
Such classes a pear in your calendar but students have to fill in a registration form before they can get access. Paid classes are a different type of self-registration classes. Unlike the regular self-registration classes the students who register for a paid class will be taken to submit a payment before access is granted.
Students who have no profiles (first time student) will be required to fill in a registration form and a student profile will be created for them. This does not automatically grant access to paid events. Access is only granted if a payment is submitted.
If you schedule paid event makes sure that your account is configured to accept payments.
You can also manage your subscribed users manually as explained in the following guide: Manage Subscribed Users.