These races weren't hold at the Colosseum but at an oval track. The biggest one called Circus Maximus seated 150,000. But in general these were free to attend.

These races weren't hold at the Colosseum but at an oval track. The biggest one called Circus Maximus seated 150,000. But in general these were free to attend. Some rich guy would pay for it to become more famous/get political power.