These are often OEM (Original Equipment Manufacturer) keys. They are tied to your motherboard and cannot be transferred to a new PC later, unlike retail keys. 3. Reuse an Old Windows 7 or 8.1 Key
If you want a 100% official retail license directly from the source, you might actually need to buy Windows 11. cheapest way to buy windows 10
You can install Windows 10 without a product key. You will get a fully functional OS, though you'll face a persistent "Activate Windows" watermark and lose access to personalization settings like changing your wallpaper. These are often OEM (Original Equipment Manufacturer) keys
If you want a full activation for the lowest price, third-party marketplaces often sell keys for a fraction of retail. cheapest way to buy windows 10