Despite the article saying $450, £350 should translate to $400.
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Even if Nintendo isn't saying anything, we all know that the Nintendo NX is arriving in March 2017. We don't know exactly what it is (a Wii U replacement or a hybrid also replacing the 3DS), and we don't know how much it will cost, but it definitely won't arrive before March. However, UK supermarket chain Tesco thinks it knows better.
A page has appeared on Tesco's website stating that the Nintendo NX Wii U (yes, they really have called it that) will release on December 31, 2016. It also had a price set at £349.99 ($450) when it first appeared, but that price has since been removed. Unfortunately, there is no image of the NX accompanying the listing.