Keys sold for $5–$30 are typically OEM (Original Equipment Manufacturer) or Volume licenses.

For guaranteed authenticity and support, Microsoft recommends buying directly from their store or authorized retailers. These licenses are "Retail" keys, meaning they are transferable to new hardware in the future.

: Major stores like Amazon , Best Buy, and Newegg sell official boxed or digital copies. 2. Third-Party "Gray Market" Resellers (Cheapest)

Buying a Windows product key involves choosing between official, high-cost licenses from Microsoft and "gray market" keys from third-party resellers that are significantly cheaper but carry specific risks.