Western Digital Elements 10TB USB3.0 Desktop/External Drie for $190, and apply code EMCDMGG53 to get $25 off.
"Desktop" means it sits on a desk, plugs into a computer's USB port, and the included power cord plugs into an electrical outlet. They do sell "portable" drives which are designed to be portable, and power themselves with their included USB data cable.
The 10TB capacity is massive, capable of storing about: 160 hours of HD-quality videos, 160,000 24-megapixel raw/uncompressed camera photos, or over 2 million jpeg photos taken by a smartphone. If you want to put the 10TB drive inside a desktop computer, grab some guitar picks and watch this video. Doing this may void Western Digital's 2-year warranty, but saves about $100 when buying an internal drive.