Looks like this is the cheapest for some time
26.40 per TB
Would have a WD 18TB CMR white label drive (WD180EDGZ, 7200RPM, 256MB Cache). Some say could be a white label of a HC550. I'm hanging out for sub $25/TB @ 18TB, which is probably only weeks away.
May require the PIN 3 mod if your PSU isn't SATA 3.3 compliant.
How do you know only a few weeks away?