Prerequisites
GCP Account
To create a GKE node pool with preemptible VMs, run the following command:
$ gcloud container node-pools create preemptible-pool –preemptible –cluster gke-cluster-1 –zone us-central1-c
It will create a preemptible node pool

Using Console
In Cluster, Click Add node pool

Give name and node version

Choose Number of preemptible nodes.
Enable Auto upgrade and Auto repair.
If you want you can choose Enable Auto scaling.

Click on Nodes in Navigation Pane.

Choose the machine configuration for nodes.
Tick the Enable preemptible nodes.
Click Create.

The Preemptible node pool will be created.