The cluster’s configuration pane allows you to delete a cluster:
Deleting is final and cannot be undone. Billing stops immediately when the cluster has been deleted, rounding up to the nearest hour. This means you can easily start a cluster, run some tests, and tear it down again when you are done.
In not too long, we will make our cluster management APIs available. This will enable you to automate the running of, for example, final integration tests before deploying to production, for a few cents. We are also looking into making it possible to pause a small running cluster. This can be quite useful when you only occasionally use a staging cluster.