Garry's Mod conundrum!

[Nautical Honors Society]

Hey guys, because of the recent sale I'd like to get Garry's Mod.

But the only source games I have are TF2, Portal 2, and L4D2.

So I was considering getting the Orange Box for $13 to have more things to edit on Garry's Mod.

But the problem is

1) I already own TF2 on Steam
2) I already own the Orange Box for 360

Is it worth getting games I already have just for Garry's Mod?

Also. how fun is Garry's Mod?

Thanks guys!

 

[Mojo]

Garrys Mod is damm fun if your into those sandbox things.
You could get G-mod and see if you like it, and if you do then get
the Orage box afterwards.
If you see its not your thing then you leave it.
You do have way more content if you have CS:S and HL2,
but TF2 allready gives you alot to work with and give you
a first impression.
You can also download a ton of maps and models from
http://www.garrysmod.org/
I say go for it and if youre having fun get the box.
Hey, maybe some of your friends will buy the extra games off of you.
Its definitely a great sandbox.