The cost is rolled into your PC when you buy it. Its not free.
Your $10 licenses are not legal. Sorry. Those are sketchy grey market keys. Though Microsoft likely won't go after you for it, so I'm not sure it matters.
You should have just saved the $10 and downloaded a cracked copy.
If they're authenticated when I install the OS, what makes them illegal?
Never had issues activating the Windows keys nor the Office keys I've bought from them. And I always get the installers straight from Microsoft.
I'm not going to switch to piracy to avoid some gray market sketchiness, as long as the keys don't seem to be stolen.
Cracked copy = trusting some shady 3rd party
You’d rather have an unofficial ISO?
Why?