Fast Money Trick
When you begin the game, in the second level when you are in the night city to meet up with luca, go right until you reach the car. Wait there and there will sometimes be men that look like french people or artists walking by. Beat each one up. For each artist you beat up you pick up $3, 000!
If the artist is walking in the opposite direction AWAY from the car, don't bother to beat him up. If you do, you will accidentally leave the mission area and you'll have to restart without the money you pick up recently.