There are many people who are waiting for Windows 10 to roll out, now the Microsoft has confirmed that all the people who have enrolled for windows insider program will get a free copy of the operating system.
This conformation was made by Gabriel Aul who is one of the main spokes person of Microsoft for Twitter, Gabriel Aul conformed this via a reply by which he made clear that users of the insider program will be able to have a free copy of Windows RTM.
Microsoft have already confirmed that you would be able to upgrade Windows 10 RTM from Windows 7 or Windows 8.X, For Windows Vista users free upgrade will not possible. The Windows vista users who like to upgrade to Windows 10 when it comes out later this year have to make a purchase in order to use Windows 10.
As per now Windows 10 is in its Beta state, the build 10074 which is the eights iteration.
For Windows 7 And Windows 8 users, they can free upgrade to Windows 10 with their genuine key. Microsoft have not yet cleared that how they intent to control the number of installs for a particular license, or transferring of license.