Amazon has the Seagate Backup Plus 4TB portable external hard drive (STDR4000100) on sale for $99.99. The drive is available in a number of different colors including red, blue and silver. It also ships free with Super Saver Shipping.
Seagate Backup Plus 4TB Portable External Hard Drive with 200GB of Cloud Storage USB 3.0 (Black) STDR4000100