Staples offers the Seagate Backup Plus Slim 4TB Portable External Hard Drive in several colors Black (pictured) for $109.99. Pay with Visa Checkout to cut the price to $84.99. With free shipping, that's a $15 drop from two days ago and the best price we've seen. (It's a low today by $24.) This 2.5" drive comes with an offer for 200GB of OneDrive cloud storage and is powered via USB. Deal ends July 22.