GTA V is 25% off at the moment in the steam sale...still £40 though
(If you plan on playing Online at all (like @ a LAN :
I'd recommend the Game + $1.25m Cashcard option as this will set you up with a High-end (10 Car) apartment and have enough cash to buy the Armoured Car at level 12 which will be almost immediately + some left over for guns etc)
