Okay, you may have just noticed that you have received a "static IP address charge" on Google Cloud Platform.
What is the Static IP address charge on Google Cloud Platform for?
Static IP address charge is for usage of a Static external IP addresses.
It means you have assigned an external IP address to an instance or a forwarding rule if you need to communicate with the internet, with resources in another network, or need to communicate with a resource outside of Compute Engine.
I received this charge on my Compute Engine where I used an external IP address when I was hosting my blog on Wordpress using the Google Cloud Platform (GCP) and turned off my Wordpress instance. As you generally are not charged for the static IP address if you are using it on an active Compute Engine instance.
Static IP address charge only if you're not using it
Interesting, you are only charged for static external IP addresses if you are not using it.
Or if the static external IP address is not "assigned to forwarding rules".
Per Google Cloud network pricing - https://cloud.google.com/compute/network-pricing
You can check whether a static external IP address is in use by making a gcloud compute addresses list request. This command returns a list of static external IP addresses and their statuses:
gcloud compute addresses list
Releasing a static external IP address
If you no longer need a static external IP address, you can release the address so that it is returned to the general IP pool for other Compute Engine users.
Note: You can only release a static IP address if it is not being used by another resource.
To do so, in Google Cloud Console, go to VPC network > External IP addresses. That is: