Amazon offers the Seagate Slim 4TB portable hard drive bundled with 200GB of cloud storage for $119.99 with free shipping. That's $60 off retail and the lowest price we've seen for this very portable hard drive with massive 4TB of space. It is USB 3 fast and is bus powered meaning you don't need to carry around power cables and it fits in a jacket/purse/bag pocket for convenient transport. Over 5,000 Amazon reviewers love this even at higher prices giving it an impressive 4.5/5 star rating.
In addition, Seagate offers 200GB of cloud storage for 2 years using its OneDrive account. Read more of this post