Bestbuy offers WD - easystore 18TB External USB 3.0 Hard Drive - Black for $199.99 (orig. $404.99) with free shipping.

Product Description:
Carry and preserve important files wherever you go with this Western Digital easystore desktop hard drive. The 18TB capacity offers ample storage space for your files, while the USB interface ensures compatibility with a wide range of devices. This Western Digital easystore external hard drive has a compact profile for increased portability, and the included WD Discovery software makes backing up data easy. 

• USB 3.0 interface
  Enables easy-to-use connection to devices. Backward-compatible with USB 2.0 for simple connection to your computer.
• Easy-to-use auto backup
  Comes with the WD Discovery backup software that lets you set hourly, daily, or monthly backup schedules and makes it easy to back up high-capacity files to your drive.
• Compatible with PC and Mac
  For use with your existing computers.
• 18TB storage capacity
  Provides ample space for storing documents, photos, music and more.
• Limited warranty
  This desktop hard drive comes with a two-year warranty.
• External design
  The desktop storage features a USB cable and AC adapter to work with most systems.
• WD Discovery™ software
  Allows you to manage your WD desktop hard drive and expands its capabilities.