Although Microsoft stores (physical) are few and far between, you can still order online from Microsoft directly. And in the latter case, they seem to be taking a lead from some 3rd party retailers by offering select Windows Phones from U.S. carriers (sans AT&T) for the low, low-cost of $0.01.
Heck, they even throw in free 'next business day shipping' and free return shipping if you're not happy with the phone. Mind you, this deal also counts for new lines, upgrades/renewal or add-a-line, which is something that some 3rd parties don't offer (often, they only offer the deal for "new customers").
The three U.S. devices that are available for a penny are the Sprint HTC Arrive, Verizon HTC Trophy and T-Mobile HD7. Sounds good to us, so if you were looking to upgrade, this seems to be a solid deal.
Source: Microsoft Store; Thanks, AK, for the heads up