It will be free when it is listed, with no expiry and no seat limit, and we have no plan to charge for what is described on this site. What we can actually promise is what clause 6.1 of the End User Terms says: a change to the fee would not apply to the subscription term you are already in — for a free Marketplace app that is the licence period Atlassian records for you, typically a year — and we would give at least 30 days’ notice of it. Clause 12.5 also lets us withdraw the app on 90 days’ notice. Neither is a plan; both are in the document, so they belong on this page too.
What is certain rather than promised: the app contains no licence check and no metering, so nothing inside it can stop working on a date, whatever happens to us.