Q: Will Windows 8.1 be free?
A. The update for Windows 8 is due at the end of 2013--Windows 8.1 will be a free upgrade for licensed users of Windows 8. It will be available through the Windows Store and would also be available as an offline update; plus, expect new Windows 8.1 media for fresh installations. For organizations with Software Assurance, there will also be an update for Windows Enterprise edition.
An 8.1 update will also be available for Windows RT, and this will also be free via the Windows Store.