About three terabytes of storage capacity, sitting on my desk today. Cost: about $200.

The IBM 3370 Direct Access Storage drive, circa 1979. This was the type of drive connected to the IBM 4341 computer - the first large-scale machine I worked on in my career. To match the three terabytes of capacity above, it would take over 6,000 3370 cabinets at a cost of $210,000,000. Since that weighs about 1,750 tons (so does a herd of 230 male African elephants), and won't fit on your desk, you'll need about 1.5 acres of climate controlled facility, outfitted with a few hundred Leiberts and more power than most small cities. Figure about a quarter-billion dollars to get the job done.

Of course, the mighty 4341 could only handle a tiny fraction of that capacity. In contrast to the MacBook Pro on my desk connected to the drives above, the 4341 ... well, that's just a silly comparison.