The Google Compute Engine Debian-9 Stretch image was selected as the basis for the scripts because it can be configured to run within the limits of the Google Cloud Platform Free Tier option. The provided gce build script, defaults to a GCE instance generated from a f1-micro-template designed to work within the "Free Tier" depending on selected options. The created instance can be quickly re-configured to increase resources as needed which may incur some fees. The Google Compute Engine requires creators to have a valid account even if using the "Free Tier". An existing Google Play account can be used for this purpose as well.
The f1-micro-template instance is an excellent starting point for any Drupal developer as it can run free while supporting a few client projects. All of the development happens on the GCE instance, the clients access the GCE instance for testing and approval, so everything remains in the developer's control until payment is received. If a client instance requires more resources, that instance can be quickly re-configured and any additional fees can be billed to the client. When the additional resources are no longer required, the instance can be reset back to operate within the "Free Tier".