OEM (Original Equipment Manufacturer) keys are intended for system builders. You can buy them from reputable sites (not eBay random sellers) for as low as $15–$30. These keys are legally grey but not cracked; they are often surplus volume licenses or region-specific keys that work globally.
: If you've previously upgraded to Windows 10 for free, you might still have a valid digital license. windows 10 activator teamos verified