There’s a lot of comments talking about used and refurbs. I personally use these types to get good deals but I also have a reasonably robust backup protocol. Not a full 321 backup but an appropriate level of risk for my needs.

My point being, if you go that route, they’re cheaper but the odds that one dies on you might be higher. Make sure you manage your backup strategy to a risk value you’re comfortable with.

That said, I’ve also had great experiences with serverpartdeals. I’ve also used diskprices.com to find deals.

Things to consider are noise, temps, power-on time, etc. For myself, temps are fairly consistent in my case and it’s in a closet so I don’t care about noise. I also don’t need particularly fast access on the HDDs (I use an nvme cache strategy as well) so I can pretty much use whatever. Your needs might differ.