DynamoDB

These stay near zero until there is traffic, and are the hardest to predict from source alone.

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  DynamoDB

  aws_dynamodb_table

  On-demand: per million reads and writes plus stored GB. Provisioned: reserved capacity per hour whether used or not.

These carry no charge of their own, though some of them govern resources that do.

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  Application Auto Scaling

  aws_appautoscaling_policy

  Free itself. Decides where between the minimum and maximum capacity the service actually sits, so it sets the bill within those bounds.

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  Application Auto Scaling

  aws_appautoscaling_target

  Free itself, and the single most useful number for the bill: the capacity bounds decide how many tasks or instances can ever run.

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  DynamoDB

  aws_dynamodb_resource_policy

  A setting on another resource rather than a resource that bills. Whatever it governs is where the charge lands.