I’m in the US so I was able to snag a lot of stuff for like $150 usd off eBay. Though my first home server was actually a mini PC which was only like $100 and is super power efficient, only using like 10-15 watts. The biggest downside though of that is that is only has two NVME slots and no SATA, because it’s a mini PC.

• buy a cheap atx case with >= 4 3.5” drive bays
• buy a mini itx mb with like 4/5 SATA ports or however you want. Btw pcie SATA hbas exist. This future proofs drives. You can also get pcie NVMe adapters or buy a MB with NVMe ports. Mini itx for the power efficiency. Beware RAM limits on some MBs.
• throw a 6000 or preferably 9000 series and onwards intel chip in there. Anything before that will have poor efficiency. Good thing about this is the socket FGA1151(??) is supports a wide range of years
• 16 gb ram min. Believe me. You’ll run out.
• for PSU, go with Corsair. Only buy tested ones with all the original cables. I recommend looking at Cybenetic’s PSU efficiency numbers. I have a Corsair PSU.
• put proxmox on it. Containerize everything if you’re low on RAM or CPU.

Just use WHOIS protection (which should be free, but whatever).