Buy 3x 16 or 18 TB external harddrives on black Friday and shuck them. It is still going to run you $400-$500. Can't do it cheaper as far as I know.
But great advice and the route I've personally taken :)
In fact they have 14TBs for $199.99 right now ($14.28/TB)
https://www.bestbuy.com/site/wd-easystore-14tb-external-usb-...