Transfer of car

Last September I bought a car with my son. He wanted to establish a credit rating. I was the co-signor even though after the first month, the payments have been made solely by me. I also pay the insurance, with me as the primary driver and my son as the casual diriver.. What it comes down to is now I want the car in my name as I do not trust my son and he is not mature enough to have a new car. I called the dealership, but they said to transfer the car in my name it would cost me $400. Is there another way of transferring the car without incurring this fee? Can we just go to the license bureau and transfer the registration?