Downloading Counter Strike

If I download counter strike from the above link.

Is it a complete counter strike pack?or would I need half-life before downloading it?

Why is it a freeware, isnt counter strike a commercial game?

u can check Note given there

"Note: This is a Steam installer, which means you need a valid copy of Half-Life/Counter-Strike. The Half-Life/Counter-Strike package can be bought via Steam for €9.99."