A buddy used to sell cars. He had all kinds of sliding scales and spiffs but essentially got 25% of the dealer’s profit on each car. Accessories tend to be more profitable than the cars themselves. He also got bonuses for hitting certain milestones.
So it’s hard to say for your car in particular, but probably somewhere between $100 and $500.
You have to remember 20 cars would be a big month for most sales people, and good sales people in all industries tend to be well paid.