Whats the best way to outright purchase iPhone X in USA?

Would like to pick up two iPhone X 256gb variant. Paying outright for both phones. I'm guessing on launch it would be pretty limited stock and people would be camping outside stores a week in advance? How long after launch should one be able to just walk in a purchase it? Anybody try purchasing from the states before? I'm cruising late January and won't mind purchasing both from the states as after conversion it's still cheaper than canada. Would it still be scarce come end of January?