You need to buy lifetime access (paid once) or subscribe to get access to all features (such as random exam, timed quiz, incorrect questions review, bookmarks and etc.), courses and questions.
Any unused portion of a free trial period, if offered, will be forfeited when the user purchases a subscription to that publication, where applicable.
Subscriptions are auto-renewable and are billed at the rate and period selected depending on the subscription plan.
Subscriptions can be managed and auto-renewal can be turned off in Account Settings in iTunes after the purchase.
Users’ accounts are charged for auto-renewal within 24 hours prior to the end of the current period.