Lambda
Terraform module, which takes care of a lot of AWS Lambda/serverless tasks (build dependencies, packages, updates, deployments) in countless combinations
Charged while it exists
1These set the floor of the bill. They accrue from the moment they are created, even if nothing uses them.
Lambda
aws_lambda_provisioned_concurrency_configProvisioned concurrency is billed per GB-second for as long as it is configured, whether the function is invoked or not — the one Lambda charge that does not go to zero when idle.
Charged by usage
3These stay near zero until there is traffic, and are the hardest to predict from source alone.
CloudWatch Logs
aws_cloudwatch_log_groupPer GB ingested, then per GB stored for as long as retention keeps it. Retention set to never expire is the usual surprise.
Lambda
aws_lambda_functionRequests plus GB-seconds: memory multiplied by execution time. Nothing when it never runs.
S3
aws_s3_objectStored GB per month at the bucket's storage class, plus the request that put it there.
No charge
12These carry no charge of their own, though some of them govern resources that do.
aws
local_fileaws
null_resourceaws
terraform_dataIAM
aws_iam_roleIAM
aws_iam_role_policyIAM
aws_iam_role_policy_attachmentLambda
aws_lambda_event_source_mappingLambda
aws_lambda_function_event_invoke_configLambda
aws_lambda_function_recursion_configLambda
aws_lambda_function_urlLambda
aws_lambda_layer_versionLambda
aws_lambda_permission