Hi Grant,
You will never be charged any amount for the first 30-days regardless of how many users you have. If you enter your credit card information before the free-period is over you do not lose any of the free days. The first payment will processed at the beginning of the next period.
You can change what paid plan you are subscribed to at any time. However, you cannot move a paid plan to a “free forever” status.
If you have specific questions about the plan, price, users or how to change or cancel anything just reach our to our team and they’ll be able to help you without delay.
Does this help?