You do not need to buy anything to start. The equipment hub explains what the parts in a normal computer do when they mine, so you can judge what you already have before spending a penny.
Your first steps
- Identify your CPU and GPU model and look up their general capabilities.
- Check your power supply has headroom before running hardware at full load.
- Make sure cooling and airflow are adequate for sustained use.
- Start with one machine and measure before adding more.