From where I'm at, I can snatch a WD Black for at least $60, and that's already a 1TB drive, brand new. If the user wouldn't be picky enough and know how to clean a drive properly, one can get a 1TB Black drive for about $40-$50, with 90-99% health.
It's a bit more expensive in here & price difference between regular 7200 RPM HDD and WD Black is quite wide while there's no significant performance difference on daily usage.
and I don't think they are selling 320GB drives brand new anymore--or I haven't stumbled upon anything within the past few years of changing systems.
So does 250GB HDD which you mentioned earlier. But if you're lucky, you could get one which never used because no one buy it
Anyway, if someone isn't that picky a Blue/Black drive secondhand would suffice and just transfer the chainstate on the OS drive which, in this case is a SSD.
I agree, but i wouldn't risk buy second-hand/used drive, even if it's properly tested before it's sold.