Due to the nature of Buy Now, Pay Later providers we can not offer yearly subscriptions on Buy Now, Pay Later (Pay in 4, Humm, Zip) on an on-going basis. You can do the initial Year Subscription using Buy Now, Pay Later but you will be required to navigate to Your Account > Subscriptions > View (to the right of your subscription) > Change Payment and this is where you can add a Credit Card for on-going payments.