I want to buy Premium, but I don't want my subscription to automatically renew.

By default, Monthly and Yearly Premium subscriptions renew automatically. You can cancel your subscription at any time if you don't want to renew automatically. You will still have access to Premium features for the time you've already paid for.

To cancel your recurring subscription follow the steps here: https://hoffmanacademy.zendesk.com/hc/en-us/articles/360011299173-How-do-I-Cancel-my-Premium-Membership