Add a one-time product

Go to the account page

Enter your registered email address - this is the email you used when creating your subscription

Click Continue

You'll receive a one-time verification code via email

Enter the code on the login screen

Select Subscriptions at the top of the page

Select the Edit products button

Select the Add product(s) to subscription button

Find the product you'd like to add

Choose the One-time Frequency option

Click the Add product button