If after your free 3 months you would like to opt out of the Annual subscription you can do so in app.
How to Cancel Your Account
On the Account tab, under Settings, click the Plan Details button. Here, you will see the plan you selected. To cancel your account, click Do Not Renew. You will be asked to confirm that you do not wish to renew your subscription and your subscription will be set to end on the free 90 days.