When you register for either the Professional or Agency plan, your first month is free. You will not be asked to enter your payment details, and you will be able to try out Ahsuite with no restrictions.

At the end of that month, you will be sent a notice by email that your trial has expired. You will retain access to all the data you entered during the trial, but you will not be able to add any new data (clients, tasks, files, etc) until you enter your payment details.