I doubt it. Maybe to Windows 7 and/or 8 users, maybe. But I honestly doubt they'd put it up for free.
At this point it's in largely in Microsoft's interest to have everyone updated to the latest OS. This is why it is very likely that Windows 10 will be free. If not completely free, at least free as an upgrade from anything that came after XP. The reason for this is that Microsoft is changing how their company makes money; from selling their flagship products (Office, Windows), to selling services
through their main products. They are doing this so they can compete better with Android and Google in general, which so far has been kicking their ass in phone and tablet sales because it doesn't cost the manufacturers anything to load Android onto their devices.