There is a setting under advanced features where you can decide to have people either supended when they cancel their subscription, or to have it where it doesn't cancel it right away, but instead it cancels it when it is scheduled to end. If it is set to to suspend when their susbscription would have ended, instead of instantly, then what happens is anyone without a payment will be suspended. You would have to manually add a payment for the member to prevent them from being suspended.
Under advanced features
change "Software Is Free" to No.
Then, on the join page (/join), you can either enter the email addresses of the people you want to give free accounts to on the right form
OR fill out the left form to create a free account.
Also, you can import several members at once from .csv file using the import members section.