Microsoft has finally shed some light on Windows 8 upgrade pricing, or the cost of upgrading Windows XP, Vista or Windows 7 OS to the upcoming Windows 8, and the actual price is surprisingly low.

According to the info over at The Windows Blog, the online version of the upgrade will go for as low as US $39.99 for Windows 8 Pro. The packaged/retail DVD version will be rolling out for slightly higher US $69.99. According to Microsoft, the Windows 8 Upgrade Assistant will check to make sure that your PC is ready for Windows 8 and let you save all your Windows settings, personal files and apps in case you are switching from any consumer of Windows 7.

Those with Windows XP will only be able to bring personal files while Vista users will get Windows settings and personal files. After purchase and settings, the Windows 8 Upgrade Assistant will kick of the download. There is also an option of creating your own bootable USB or .ISO file to burn on the DVD or you can purchase a backup DVD for US $15 + shipping.

Of course, Microsoft was keen to note that these are all "promotional prices" and will be so until January 31st, 2013. It is also expected that the prices will rise after the end of the promotion. The download will be available for over 100 countries and in 37 languages.

You can check out more details at The Windows Blog.