According to http://www.forbes.com/sites/netapp/2012/10/11/windows-8-release-date-tablet-microsoft-cloud/ http://www.forbes.com/sites/netapp/2012/10/11/windows-

According to http://www.forbes.com/sites/netapp/2012/10/11/windows-8-release-date-tablet-microsoft-cloud/ http://www.forbes.com/sites/netapp/2012/10/11/windows-8-rele..., Microsoft plans to spend 1.5 - 1.8 Billion dollars marketing Windows 8. That's 45$ of marketing costs per copy of Windows 8 sold to date.