AWS now support AMI Billing information
So, new announcement from AWS caught my eye - https://aws.amazon.com/about-aws/whats-new/2020/02/amazon-ec2-adds-ability-to-easily-query-billing-information-of-amazon-machine-images/
From the documentation it seems like now we can have 2 points of truth regarding purchasing or RIs platform information (if you're not already using Saving Plans), but the better thing is that you can now have a gateway to your provisioning with better billing visibility if you're using the right AMI for you.
From the documentation:"You can determine the platform details and billing information associated with an Amazon Machine Image (AMI) before you launch an On-Demand Instance or Spot Instance, or purchase a Reserved Instance. For Spot Instances, you can use the platform details to confirm that the AMI is supported for Spot Instances. When purchasing a Reserved Instance, you can make sure that, for Platform, you select the correct value that maps to PlatformDetails on the AMI. By knowing the billing information before launching an instance or purchasing a Reserved Instance, you reduce the chance of erroneously launching instances from incorrect AMIs and incurring unplanned costs."
Feel free to explore! https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ami-billing-info.html