Amazon recently ungated all of their previously paywalled data tables in AMC. However, you still need to enable them.
In Amazon Marketing Cloud in the Ads console, click on “Paid Features”.
Scroll down to the Amazon Retail Purchases table and click “See Options”.
If you cannot click into “See Options”, then you will need to open a support case with Amazon in order to get access.
Agree to the Terms and Conditions and hit “Subscribe”.
It may take up to an hour to become available.
