From my own experience, I think it's probably better to bring someone who knows how to get a bargain on the car that you want because when u face the situation in person, u may hesitate to negotiate the best price EVEN If you know how to it. But it also depends on the model and year of the car you are getting at. If u buy a Toyota, it's hard to negotiate nowadays. It's easier to negotiate the price if the car is a year end model or it is not a popular model.