Short version: EBS snapshots cost $0.05/GB-month and nobody ever deletes them. Backups from volumes and AMIs that were removed years ago keep billing. For snapshots you must retain but rarely touch, the archive tier is ~75% cheaper ($0.0125/GB-month). Here is how to find the pile, delete what is dead, and archive what is not.

Short version: Amazon Redshift bills per node-hour whether the cluster runs a million queries or zero. A multi-node cluster left over from an old analytics project can run hundreds of dollars a month for nothing. Here is how to find idle clusters and stop the bleeding - pause, snapshot-and-delete, or move to Serverless.

Short version: With provisioned DynamoDB capacity you pay for the read/write units you reserve, used or not. Tables are routinely over-provisioned "to be safe" and then run at 5-10% utilization for years. Here is how to find them and pick the right fix: right-size, turn on auto-scaling, or move to on-demand.

Short version: By default, a CloudWatch log group keeps logs forever. Stored logs cost $0.03/GB-month, and every Lambda, ECS task, and API Gateway you have been running for years has been piling them up. Setting a retention policy is a one-line fix per log group. Here is how to find the never-expiring ones and cap them.