Google Cloud Nightscout » Why have I been charged for Storage PD Snapshot?
A snapshot is a compressed backup of disk data. For example, a snapshot of a 30GB disk that is about 15% full would be approximately 3.3GB. Snapshots are not free and incur costs. You can review specific pricing details on Google Cloud’s pricing page. A 3.3GB snapshot costs about $0.25 a month.
To minimize expenses, delete snapshots as soon as you no longer need them.
If you need to investigate a charge, the most effective method is to create a cost table in your Google Cloud account. This will help you track and identify charges related to your snapshots and other resources.