This is not a memory stick, it is a SSD external hard drive. Currently 1TB of SSD is around $370 and not available here yet, but soon. As we all know, the size will double over the next few years and I expect by 2020, 4TB will be available.
Much smaller the a WD Book or Cloud Drive this is a game change, more like the size of a memory key.
You cna buy it for around $100 for a 256GB version.
See https://www.wdc.com/products/portable-storage/my-passport-ssd.html?cid=wdstoreUS:email:mpssd:shopnow2:na:das:mpssd&mkt_tok=eyJpIjoiTWpVM05qSmpaakZtWm1WayIsInQiOiIxdFVuMnhnQk1PNjRMaXlUNlVETDVCQnBSZlJCakJcL0hobFBMWG9nbWVaRUxud25cL3l2ZU9lM21sMDhkUW5RckFcL211WGF0UVhQeXBmN1o0N2ZXMXdxblJsdkZXTUM3VXJBZzJ1Vm56em1WYmFxRnRrbnBoNFwvZU50UmROOFNJWXAifQ%3D%3D for more info