Agreed. I ran a small GPT chatbot on Lambda through API Gateway with a dynamodb storage backend and don't recall incurring any cost (or if I did, was just pennies per month).

It "scales to zero" as soon as the request stops as far as billing is concerned.

However, the image remains "warm" and incurs zero cost once the last request ends. So I usually have a `/heartbeat` endpoint for this purpose and point a Cloud Scheduler job at it.

I haven't read the docs to figure out the exact heuristics of when it becomes "cold" again.