Officially, Microsoft has sold out of the just launched white 2TB Xbox One S, although it's available from third-parties at higher prices. The Microsoft Store in the U.S. is still selling that version of the console, at least for now.
According to Eurogamer, the white 2TB launch edition version console, which had the price of £349 when it started shipping in the UK, is now out of stock and won't be replenished. It is available at third-party retailers, but at much higher prices. Microsoft is selling the red Gears of War 4 edition of the 2TB Xbox One S for £399.99 that will begin shipping on October 5.
At the moment, the Microsoft Store in the U.S. is still selling the white 2TB launch version of the Xbox One S for its normal $399 price but it appears that supplies are limited so if you want one, you might want to work quickly before they are sold out in the States as well. Microsoft is also taking orders for the white version of the Xbox One S in 500GB models for $299 and 1TB models for $349; both of those will begin shipments in the U.S. on August 23.