Back in May 2021, during the //BUILD/2021 event, Microsoft announced the ability for Microsoft Teams users to purchase any third-party Teams app subscriptions directly from the Teams app store. From within the store, users can view subscription plans offered and go through the checkout process to pay with a credit card.
This feature is soon going to roll out to the Microsoft Teams users and the tenant admin can enable or disable their users' ability to discover and install third-party applications that require third-party subscriptions.