I get mine from a link on diskprices.com
Usually lead to ebay or Amazon - I’m not particular.
They’re almost always used business drives. Oldest one is now 4 years running.
Edit: My major exclusion is SMR, since I’ll be using them in a NAS of some kind (hardware or Proxmox). Today I’m all SATA - if you can, go with SAS, drive costs are lower.
Businesses replace drives and systems on a schedule regardless of true wear on them - their risk vs cost metric is very different than ours.
So used business hardware is a great value for those of us who have a sunk cost in labor/expertise.
Most drives I’ve owned have run for 10+ years, while any business won’t run them past 5. I can take the risk of losing a drive, while it’s more important for a business to prevent losing a drive. Business disruption is a more costly event.
Rat farts!