Ebay and decommission. I got really lucky on my SSDs, those were all from a decommission. Company was going to pay an ITAD for destruction. I picked it all up and wiped it on site. The rest are relatively cheap hardware, supermicros and such... but with enough of them you can build a resilient cluster.

A lot of my stuff is Ebay... I did recently purchase a new rack as probably the only "new" item I have in regards to my setup. The old one had issues... and I didn't want to deal with thrifting broken racks anymore. And I needed a taller 45U rack rather than a 42U standard rack... Also the more depth means I can accommodate the 60 bay server in the future if it comes to that.

But things like 40gbps networking... ebay. The proxmox servers are decomissioned. the truenas server was ebay. switches was ebay.. Oh! The firewalls... That was new purchase. I am stupid lucky to live somewhere with 8gbps fiber. I needed real horsepower to push that with IDS/IPS enabled. So this was a new purchase from supermicro. The SAS spinning rust drives I picked up on Reddit homelabsales or something like that a while back. PDU's were ebay... UPS were ebay... Expansion batteries were craigslist. Most cables were new from FS

Previous versions of my rack were government liquidation/auctions. My dad has a lot of that equipment now. I found one auction that was 1400$ that was basically a whole racks worth of shit... most of it pretty usable 12 and 13th gen dells. And another auction for 600$ that had a dell m1000e with some 4TB of DDR4 ram...

But you can do a lot of this shit with a cluster of little N100 boxes if you really wanted. I just happened to get my hands on enterprise level equipment... So I joined the Romans...