Here is a list of cheats for The Getaway and The Getaway: Black Monday.
The Getaway:
Free Roam Mode
During FMV before the Press Start screen appears press Triangle x3, Left, Square, Triangle x3, Left, Circle. A womanly sound confirms it.
Infinite Ammo Cheat
During FMV before the Press Start screen appears press Up, Down, Left, Right, Triangle, Up, Down, Left, Right, Square. Repeating disables it.
Cutscenes Heel Cars
If you have a wrecked car and a cutscene plays it will repair the car.
Unlock The Armored Car Weapon
During FMV before the Press Start screen appears press Up, Down, Left, Right, Square, Triangle, Circle.
The Getaway: Black Monday:
Double Health
During FMV before the Press Start screen appears press Up x2, Left x2, Right x2, Circle x2, Down.
Infinite Ammo
During FMV before the Press Start screen appears press Up, Down, Left, Right, Triangle, Up, Down, Left, Right, Square.