I just did google and found this links for changing xbox locations:
http://support.xbox.com/en-US/my-account/microsoft-account/update-microsoft-account-country-region
https://www.bestvpnprovider.com ...
You can just change your location at the bottom of the webpage to US and then the store should start displaying all of the XB1 games available with $ prices. Normally you can't just buy the games in $ ...