B&H Photo Video offers the Western Digital 3TB Elements USB 3.0 External Hard Drive for $89.99. Coupon code "BACKUPSRP" cuts it to $69.99. With free shipping, that's the second best deal we've seen and lowest price we could find by $19 today. (We saw it for $5 less on Black Friday.) It features cloud backup and is compatible with Windows and Mac.
Reviewing this critical insurance policy takes a little effort, but it pays off big.