Do I have to pick a franchise when starting my own dealership?

No, I think that's a bad idea. By picking a franchise, you're forced to let them make most of the profit. For example, if you sell new Fords, Ford manufactures a vehicle for maybe $10,000 and sells the vehicle to the dealership for about $49,500. The dealership then sells the car for $500 over cost. If you open an independent dealership and sell used cars, you can buy a car for 140% of the book value if you're securing financing for the customer, and as much as you want if the customer pays cash. Most used car dealers make about $3000-$5000 per vehicle, and most new car dealerships make $200 to $500 in profit. Sales staff usually work on commission, receiving 12-25% of the gross profit in the front end.