Yes. Every new calendar starts with a 7 day free trial, and all features work during it.
If you have not chosen a plan, the calendar stops updating until you subscribe. Your connected calendars and settings are kept.
Each plan sets how many properties and calendars you can connect and how many extra share links you get. The plan picker lists the limits for every tier side by side.
Open the plan picker from your account and choose the plan you want. Upgrades take effect right away.
Open the plan picker and choose to cancel. You are taken to the secure billing portal to confirm.
Open Payment History in your account. Each payment has a "View receipt" link.