Of course. But you only get 1 key. If you use the same key for more than 1 computer it will be invalidated.
Since you are buying a regular retail key, you can always get the windows 10 license transferred from one computer to another if you decide to throw away an old computer or if you change your motherboard (changing motherboards can invalidate non-retail keys.
You can always get a cheaper OEM/System builder license, but be aware that like I said changing motherboards could invalidate your key, and depending on where you get the key from, the key could have been obtained illegally (meaning that Microsoft can one day decide to make your windows 10 license invalid because you bought it from a fraudulent seller)