The Pro Trial plan is a plan intended solely for internal non-production purposes, such as evaluation and testing, while fully complying with the Acceptable Use Policy outlined in the Terms of Use. It is available free of charge for a limited amount of time. You can upgrade to the Pro Trial plan if you want to experiment with more robotic power and premium services. With a Pro Trial plan, you can try the extended platform capabilities that come with a paid Pro plan. The evaluation period is limited to 60 days. After the trial expires, your organization is automatically downgraded to the Free plan1.
Reference:
Automation Cloud - About licensing