Let's say a car is worth $25,000, but they list it at $30,000. A buyer who negotiates a 10% price drop to $27,000 may feel like they're doing well because they're measuring the result relative to the starting price. But they're still overpaying by $2,000, and in that case, the dealership actually took the customer to the cleaners.

Do your research. Know the value of the car based on market transactions. That's the only way to get the best deal possible.