Can I still get an free Win-10 upgrade to my Win-7 machine?

Short answer is no. That offer was over about 2 years ago. There are some ways to install it, but it will be watermarked and you won't receive security updates. A copy of Window 10 Home is only about $90 at Amazon and the best thing to do is just get a legal copy.

Maybe
https://www.windowschimp.com/windows-10-free-upgrade/

Those are the same tricks mentioned at multiple websites including howtogeek. So, "maybe" is the right answer, rather than no.

I've gotten two Windows 10 Pro keys from Windows Chimp for $80.

Windows 10 Home Amazon

Also, depending on the age and capability of your current computer, and what you're using it for, you might want to consider getting a new computer instead of putting Windows 10 on an older one.

Windows 10 won't automatically turn an old computer into a new one, so unless you're only playing casual games and other games with low requirements, you might be better off with a new computer.

Excellent point.

Good Point. Thanks for the info.