Adorama via eBay offers the the Western Digital 3TB Red Serial ATA 6Gb/s Internal Hard Drive, model no. WD30EFRX, for $132.98. The Western Digital 3 TB hard drive runs quietly with no vibration and reads and writes fast, so users will not notice any delays. It has a read of 207 Mbps and a write of 190 Mbps for fast performance. Amazon customers gave it 4.5/5 stars and great reviews.
If you’re looking for a NAS to put them in, look no further than Synology.