While the Xbox One and PlayStation 4 launches started off with Microsoft and Sony trading congratulatory tweets, Microsoft has stepped up its marketing recently. In promotional emails, the software giant is offering $100 towards an Xbox One when people ditch Sony’s PlayStation 3. The trade-in deal is only available at Microsoft’s retail stores in the US, and it applies to the PS3, Xbox 360 S, or Xbox 360 E. The promotion reduces the $100 gap, and brings the Xbox One price down to the same $399 as the PlayStation 4.