If someone is using Windows 7 or 8, he will get a free upgrade, irrespective of whether he has paid for it or not.
"Anyone who is having a competent device can upgrade to Windows 10, including those with pirated copies of Windows.
"Microsoft Windows" is a well known operating system for every computer user in the world. Recently they have released windows 8.1 update for their existing Windows 8 users. People were waiting for the next version of Windows for a long time but the company oddly skipped a number 9 and going to launch Windows 10 next year. According to the Microsoft this will be the most comprehensive platform ever in the history of the company.