Great place to start is with an Antminer from nostr:npub1q4zl8v0cpeu0lv47msq2z0jpkr2q3wq5d4ukylxg9sx7t7rcz0uq5ftv7q, have bought three S9’s from them so far.

You can reach out to them on Telegram too.

Already fitted with easy to use firmware (Braiins OS). I run an S9 in my garage as a heater and just for the principles of it.