Before starting to buy any hardware, you should try out the metal-stack on your notebook and familiarize with the software.
For this, we made the mini-lab.
The mini-lab is a fully virtual setup of metal-stack and is supposed to be run locally on a single machine. For this reason, the setup was slightly simplified in comparison to full-blown setups on real hardware. However, the lab should help to understand all ideas behind the metal-stack.
Get your hands dirty and follow the guide on how to get on with the mini-lab here.