http://www.pricespy.co.nz/c_687.html?d=14976
http://www.laurenson1.co.nz/shop/show_category.php?cat=200

This website lists the price for WD20EADS 2TB Greenpower Hard Drive for $345 (~17c per GB) which would bring it in line with the pricing for other lower capacity hard drives.

This price is approximately $155 lower than what the next cheapest retailer offers this model at so I'm assuming that this seller has made a mistake.

If the price is for real then I'd probably buy 2 or 3