Some licenses are specifically sold for refurbished PCs and may be available at lower costs, often around $50.
You can sometimes find unused OEM or "System Builder" retail packages on sites like Amazon or through specialty software vendors. Prices for these can range from approximately $50 to over $100 depending on the edition (e.g., Professional or Ultimate). buy microsoft 7 product key
If you already own a computer that had Windows 7, you might not need to buy a new key: Some licenses are specifically sold for refurbished PCs