https://www.gamespot.com/articles/xbox-one-x-pre-order-guide-amazon-gamestop-best-bu/1100-6452672/

September 20 update 2: Xbox One X pre-orders have gone live at multiple retailers in the US. For as long as they remain in stock, you can pre-order through Amazon, Best Buy, GameStop, Target, Microsoft Store, and Newegg. The previously announced GameStop bundles range in price from $570 to $800, although the system is also available on its own, too. Keep in mind these are the standard editions, not the Scorpio edition. They offer the same functionality; you'll simply be missing out on a special design and a free vertical base that allows you to stand your console upright.

September 20 update: GameStop's Xbox One X pre-orders go live today, and Microsoft has announced that a number of other retailers will also follow suit. These include the Microsoft Store and Amazon. We'll report back with more specifics as they're available.