Syncfusion offers downloads of Essential Studio WinRT (XAML) for Windows for free. (No credit card is needed; after adding it to your cart and completing the order, you'll be sent a license code via email.) That's $399 off and the lowest price we've seen for this software, an enterprise-class toolkit for building Windows Store apps. It includes one year of support and updates.

Link: http://www.syncfusion.com/sales/offers/buildwinrt