We currently have Monthly, Annual & Lifetime Premium Memberships options available.
The price for a Membership varies depending on which country's App Store you're making the purchase from.
You can find the applicable pricing for your geographical location on our App Store page here. Scroll down to the "In-App Purchases" section and the pricing for each Membership tier will be displayed there.
Alternatively, enter the Portal Library (swipe down on the main interface) and tap on the gold banner, and localised pricing for each Membership tier will be displayed on the subsequent screen.