As of 3/14/2025, I have confirmed Azure doesn't not support authentication using retail API. Hence, it is not possible to retrieve the Enterprise agreement pricing using the retail API as questioned earlier.

Option 1: Use Azure pricing calculator, sign in to get enterprise agreement price.

Option 2: (Requires EA admin or Enrollment reader role over EA billing account)

To retrieve EA pricing, download cost management price sheet as .csv file. Write automation script to filter price of any resource. One simple way would be using Meter ID.

Option 3: (Requires EA admin to sync EA pricing sheet to storage account)

If you do not have EA admin or Enrollment reader role, you can ask the admin to sync the pricing sheet to storage account. Finally get access to storage account and write automation to retrieve the pricing of desired resource. Here is the Azure documentation for improved exports experience.