Platinum Micro via eBay offers the Seagate Barracuda 2TB Serial ATA 6Gb/s Internal Hard Drive, model no. ST2000DM001, for $99.22 with free shipping ($0.05/GB). That's the lowest total price we could find by $4, outside of the prices below, although we saw it for $30 less on Cyber Monday. It runs at 7200 rpm and features a 64MB cache.

Close prices: TigerDirect and Better Choice Online via Amazon charge $99.99 with free shipping.