I see scalpers have been selling the XSX for less than MSRP if you include with tax.
It's now available on the Microsoft site without the need to buy anything else (it's been available for a little while, but you had to get a game, controller and/or 3mo GassPass).
The XSS has been available on and off since launch, and frankly makes a lot of sense if the extra storage isn't a deal-breaker.
Costco (perhaps amazon, too) have $100 MS gift cards for $90 and sometimes $80, so it's possible to get a XSX for less than $500.