Terms of Subscription:

Monthly: $8.99 per month.

Payment will be charged to the iTunes account within 24-hours earlier to the end of the free trial period.
Note: You can cancel your subscription at any time during the trial period without any charges.
Renewal
Renewal: subscription automatically renews unless auto-renew is turned off at least 24-hours before the end of the current period.
Payment will be charged to iTunes account within 24-hours prior to the end of the free trial period.
The account will be charged for renewal within 24-hours prior to the end of the current period.
To manage your subscriptions or turn off auto-renewal:
Go to settings > iTunes & App Store;
Tap your Apple ID at the top of the screen;
Tap View Apple ID. You might need to sign in or use Touch ID;
Tap Subscriptions;
Tap the subscription you want to manage;
Use the options to manage your subscription.
No cancellation of the current subscription is allowed during the active subscription period.
Any unused portion of a free trial period, will be forfeited if you purchase a subscription to that publication.