It's not free... I need to have paid for a valid Win7 or Win8 license to qualify for "free".
So far, I've installed Windows 10 four times. Three of them have been on computers I bought used using the used computer's COA.
Actually, when you claim that it is not a free upgrade because you need to have paid for a valid license for the software you claim to be using, you are implying that you stole Windows.
The other poster appeared to be presuming that that implication was unintentional and inaccurate, and that the upgrade was indeed free for you.