BuyDig via Rakuten offers the Seagate Backup Plus 4TB USB 3.0 External Hard Drive for $94.99. Coupon code "BYD15" cuts that to $79.99. (You must sign in to your Rakuten account to use the code.) With free shipping, that's $10 under our August mention (although that came bundled with an $18 Rakuten credit) and the lowest outright price we've seen. (It's the best deal today by $19.) It features mobile backup via its app for iOS or Android. Deal ends November 10.