Depending on where you live, you may find it in your best interest to own a car. If you choose to live within the city area, however, a vehicle is an unnecessary expense as public transportation is easily accessible and parking is very difficult to find. However, as soon as you move into the outer districts of the city and into the GTA, a car becomes a necessity.
Other than during the morning and afternoon rush hours, traffic in the GTA is reasonably smooth. The 400 series highways provide an excellent way to rapidly traverse the city without getting into the maze of downtown streets. Other than the 407, which is a toll route, all roads and highways are free to use.