Windows 10 is a Free Upgrade for Existing Windows 7 and 8.1 Users
Microsoft has basically followed in Apple’s path, and made Windows 10 a free update for their existing consumers. There are limitations and this will only be applicable for the first year, which does not seem to be much of an excuse for complaining.
To explain it further Microsoft states :
This is more than a one-time upgrade: once a Windows device is upgraded to Windows 10, we will continue to keep it current for the supported lifetime of the device – at no additional charge. With Windows 10, the experience will evolve and get even better over time. We’ll deliver new features when they’re ready, not waiting for the next major release. We think of Windows as a Service – in fact, one could reasonably think of Windows in the next couple of years as one of the largest Internet services on the planet.
Enterprise customers are not left behind and continue to get the same service and support as previous paid “enterprise” versions.