Buy a savings plan for an Organizational Unit, with consolidated billing configured for root Organizational account

Create a shared pool account as a Savings Plan account, follow these steps:

1. Sign in to the AWS Management Console using the management account credentials.
2. Go to the Billing and Cost Management console.
3. Navigate to the "Preferences" page within the Billing and Cost Management console.
4. Look for the option to enable RI/Savings Plan sharing. This setting allows you to share Reserved Instances (RI) and Savings Plans across accounts.
5. Enable the RI/Savings Plan sharing option.
6. Specify the particular account ID or multiple child accounts that you want to include in the shared pool account.
7. Save the changes to apply the sharing settings.

By enabling RI/Savings Plan sharing and specifying the account ID(s) to include, you are allowing the specified account(s) to purchase and utilize Reserved Instances and Savings Plans from the shared pool account. This helps in centralizing the management and utilization of RIs and Savings Plans within the designated accounts.

Please note that the exact steps and options may vary slightly depending on the AWS account structure and the version of the AWS Management Console. It's always recommended to refer to the official AWS documentation or contact AWS Support for specific guidance related to your account setup.