While the Add-Ons store is open, a banner will appear on your homepage indicating you may now shop. You can click the banner to access the store, or click Shop > Add-Ons on the top menu bar of your account. The Add-Ons store is only available for Active members.
The Add-Ons store remains open for a limited time. Add-Ons are available for purchase every month while the Add-Ons store is open, except on months the PopUp store is featured. Event dates can be found on your personalized calendar on your homepage (you must be logged in to see it).