So I was going to buy Garry's Mod

Happy to hear it

You were gonna buy Garr' ?

Umm... And then what?? You were going to buy it?? Well tell us the rest of the story, did you buy it or not?? I wanna know :P

Edit: Okay now my curiosity is satiated. Nothing to do here anymore.

Yeah sorry it posted before I finished.

I think TF2 would work

You only need 1 Source game, Portal, HL2, TF2 etc. (Here is a list)

Just look in the "Tools" section of you library if there is the "Source SDK" if it's there and downloaded it should work

Edit: You can try downloading a free Source mod and if it works you can buy Garry's Mod

TF2 works.
And Half Life Deathmatch counts pretty much as Half-Life 2. It works.

But Each Source game can be imported and you can use their stuff.

Get CSS. Most servers use resources from CSS so your kinda fucked without it.

Alright thanks guys. I'd use it yes for single-player, but also for multilayer like Trouble in Terrorist Town.

You can play without the other games by downloading the needed content from this site. http://cscheater.comeze.com/downloads.html
This is allowed since it does not actually give you the other games and is counted as an add-on for garry's mod.

You need to have purchased a Source game, the free HL2: DM doesn't count!

The vast majority of content requires assets from CSS, so I heavily recommend getting it; though it works with a purchased Source game like HL2. I am not sure if TF2 counts anymore.

the game is a piece of shit and garry is a fucking asshole. don't buy it.