Your Garage - Parking Garage

The door to the add-on parking is in the back right of the garage. You need to unlock this if you want to purchase cars at the Auctions Center. That is where you can make the real money, by buying, rebuilding, and selling cars.

Keep in mind you cannot put client vehicles in the garage. There is also the fact that the Parking Garage is expensive, expansions get more expensive as you go along, and space can still feel limited as your collection of vehicles grows.