It's a combination of weight and size of the box. My group ordered 4 cars from Hobbynet about a year ago. If we ordered 1 car, the shipping was $60. 4 cars was $80 so it made more sense to buy them together and only pay $20/ea for shipping. I guess there is also the psychological part of it that makes you feel like crap when you pay $20 in shipping for a $14 part. I feel a lot better paying $30 in shipping for a $200 item.