Subscriptions
Subscriptions are billed to your App Store account and renew automatically until cancelled at least 24 hours before the end of the current period, in your App Store settings. Free trials convert to a paid subscription unless cancelled before the trial ends; any unused part of a trial is given up when a purchase completes.
One-time purchases
Credit packs and lifetime unlocks are one-time purchases charged to your App Store account. Without a subscription, credits are tied to the device they were bought on.