GMod 13 and Steam Winter Sale Questions

First of all do I have to already own any source engine game on steam? And will it be 75% off during this winter sale?

EDIT: By the way, is this forum related to Steam version or cracked version?

Like poking a stick in a bear

Garry made garry’s mod , garry is the owner of facepunch , what do you think ?
If on a game stands 75% sale , it is 75% sale , and you do not need any games for it.
oh and Christmas sale is aslong as it is Christmas.

I recommend you get counter strike source and half life 2 if you want to fully enjoy garrysmod without annoying error signs and missing textures. And also who is dumb enough to go through all the trouble to get a cracked version when the game is only 10 dollars?