I spent about $200 for the full set up. Granted, I pimped mine out with some add ons from @cryptocloaks so you can build one for much cheaper. I use the Umbrel implementation and learned from nostr:npub13g07ylkcawqjdkwwzhzm8swdwzmnknqpeh2qejumrqzvv6njqtds8evg79 YouTube tutorials