With the Starter membership, you can choose highly discounted items, also known as "add-ons," directly in your account during the add-on period. Add-ons may change every month and they can be seen in your account from the 20th-last day of the month (there is no pre-viewing beforehand).
The add-ons are different from the regular Artisan Shop as they are only for subscribers. If you click on "shop," it will take you to the Artisan Shop, and you will not be able to use your add-on credits there.
For more information on add-ons and how to tell that you've added them, please click here.