My average cost per usable TB is around $11 per TB, but most of my drives are smaller used SATA/SAS drives. My main pools come out to about 450TB of usable storage.

Edit, Copy paste from the post I never got around to making.

Main Pools 2023, are on 24/7/365 - 360-420 Watts.

I use 3 UPS units to protect them.

Name | Usable TB | ZFS | vdev | Drives per vdev | Drive size |Estimated total cost|Content|Notes| —|—|----|----|----|----|----|----|----|----|----|----|---- Main | 65.90TB | RAIDz2 | 1 | 8 | 12TB |$960| Content | New drives | Main | 76.50TB | RAIDz2 | 1 | 8 | 14TB |$1200| Content | New drives | Main | 87.86TB | RAIDz2 | 1 | 8 | 16TB |$1120| Content | reconditioned drives | Backup0 | 176.91TB | RAIDz2 | 2 | 12 | 10TB |$1500| Backup | used + new drives | Temp0 | 12TB | EXT4 | 1 | 1 | 12TB |$120| Temp | new drive |

Main pool - 261.26TB, This is all 1 pool, but I broke it up on the list since I use 3 different drive sizes.

Total usable TB : 450.17TB

Total Cost : $4900 / 450.17TB = $10.89 per usable TB, not bad considering the amount of drives were purchased new.