The free trial is 30 days and does not require a credit card to start. During the free trial, teams get unlimited access to all Matter Pro features listed here.
At the end of the free 30-day trial, all features of your Matter channel and web app will be locked. For example, team members will not be able to give or receive kudos and Feedback Friday will not occur.
At any time during the free trial, you can add a payment method to upgrade to Pro and keep using Matter past the free trial. You will be notified when your trial is coming to an end.
Note: If a free trial ends, you can still add a payment method and retain your team's information (kudos, feedback, etc.) saved inside the Matter-based Slack/Teams channel and web app.