In order for Garry's Mod to work you need a minimum of one Source Engine game eg. Half-Life 2, Team Fortress 2 or Portal.
Garry's Mod is only for Valve-released games, so no.
Buy Garry's mod 10 off of steam.
No you need the full game or any other source engine
Yes, garry's mod will work with portal and you will have all the HL2 stuff.
technically yes, there were a few updates it is still called Garrys mod 10 though
Garry's Mod 10
For Garry's Mod to work, you need to have downloaded at least one Source® game. This could be Half-Life 2, Counter-Strike:Source, or Team Fortress 2.
It may work but it will be extremely slow and likely to crash a lot.
no because garrys mod requires that you have a game that uses the source engine
Nope but it is useful, for example when you are using thrusters
Garry's Mod has now updated and includes all features of 13 Beta
Garry's mod tornado