Anarchy: Rush Hour

You start the game with one car that is given to you: The "Rampage". That car does NOT count. You need to participate in few events, to gather some in-game cash. Then go to the "Garage" and scroll right to the 3rd option - "Car Dealer".

Hit to enter the "Car Dealer", then purchase 10 cars from the available list based on what you can afford. The trophy will unlock after you purchase your 10th vehicle, but the "Garage" will show a message "car purchased" under 11 vehicles.

Again, the first car, the "Rampage", is given to you, so it doesn't count. The game starts you off with $50,000. If you were to buy the very first and cheapest cars on the list after the "Rampage", you would need $595,000.