I'm sure this questions is buried here somewhere in the forums but I just wanted an updated answer in 2020. If I download windows 10 and install it via Boot Camp, will Windows 10 be free or will I have to pay for it?
Sorry for the dumb question in advance,
Rich
You need a valid Windows 10 license in order to install and use Windows 10 on any computer that can run it. An Intel Mac running Windows 10 via Boot Camp is no exception.
That being said, most new name brand PCs will come with a Windows 10 license embedded on the motherboard, so it won't seem like you need a license to use and activate it, but you still do (it's just being handled automatically without you having to care). Needless to say, Apple will not have embedded a Windows 10 license on your Mac's logic board.
Windows 10 licenses are not free, however that doesn't mean that there aren't free ways to obtain one that will suffice for the purposes of installing Windows 10 on your Mac.
My advice if you need a Windows 10 license key: find a discarded Windows 7 PC that has a product key sticker on it (especially one that is too old to reasonably run Windows 10 with proper driver support), either remove that sticker or just jot down the key, and then use that key to license Windows 10. It will work.
Windows 10 install media is, however, IS free and can be obtained by going to the Microsoft website and downloading the current ISO for the current Windows 10 release (Windows 10 v2004 as of this comment posting).