We don’t automatically start subscriptions on our hosting, so there’s no need to worry about canceling. If you stop using your trial and do not subscribe we will decommission it automatically.
After signing up for a trial you might notice a small $1 charge on your card, but that should be reversed within a day… the primary reason we require a credit card is to prevent spam sign ups, and the check works by making a small pending charge and then cancelling it.