You don’t need much to get started in homelabbing and Kubernetes.
Here’s my pile:
2017 iMac
2010 MacBook Pro
2019 Lenovo 14s
All parked in the shop connected to my home network. All old systems I had lying around. I currently have the Lenovo running Proxmox, and the two Apples are my K8s cluster.
Just scrounge up what you have and get to it!