I ve spent a lot of time working with AWS infrastructure, and one thing that always annoys me is how sneaky all the costs are.
AWS Cost Explorer will show you that you spent money, but it won't easily tell you why. Things like broken 10-day-old file uploads sitting in limbo, or versioned buckets piling up old file copies because no one set an expiration rule, quietly eat your budget without triggering any alerts.
I originally wrote a small script to find these "ghost" costs on my own setup. It saved me money immediately, so I decided to turn it into a hosted tool called GhostTrace (S3 Passport).
