Seagate 16TB HDD Exos X16 7200 RPM 512e/4kn SATA 6GB/s 256MB $556 Delivered @ Technology Titans via Amazon AU

I think this is cheapest it ever been. Works out to approx. $33.25/TB at Newegg and $34.75/TB at amazon.
Also available at Newegg for $532.40 delivered if you are not in hurry and can wait for few days.
https://www.newegg.com/global/au-en/seagate-exos-x16-st16000…

Digital storage capacity 16 TB
Hard disk interface Serial ATA
Brand Seagate
Hard disk size 16 TB
Form factor 3.5-inch
About this item
Industry's first 16TB drive
Standard Model FastFormat (512e/4Kn)
Helium sealed-drive design delivers lower total cost of ownership through lower power and weight
Digital environmental sensors to monitor internal drive conditions for optimal operation and performance
Proven enterprise-class reliability backed by a 2.5M-hr MTBF rating