You purchase an annual subscription which begins with a 1-week free trial here. On that page, you can also purchase a lifetime subscription.
You can also start a free trial and make an in-app subscription purchase through iTunes or Google Play by tapping one of the locked meditations in the app. After completing the free trial of Calm Premium, you will be charged for an annual subscription.
If you would like to purchase a 1-year subscription as a gift for a friend, please do so here.
Please note: We are not able to modify or directly refund subscription purchases made via Apple's AppStore.