Expect to pay around twice as much as you would for that 2TB hard drive. Likewise, most 4TB external SSDs start around $300, and most 8TB models start at $600 and up. Should I Get a Desktop Hard ...
And, of course, you should always have an external ... with 1TB drives costing around $100/£150, whereas that same amount of money can get you a 4TB basic desktop hard drive with a USB interface ...