Does anyone have a ball park figure on how much private car or taxi costs from Beijing to Mutianyu?

I have done this section of the Great Wall twice now (I love it) but HATE taking the bus (916 express). call me lazy but that bus is PACKED every time coming back into Beijing and just after hiking the Great Wall for hours, the last thing I want to do (again) is stand for a 2 ish hour bus ride.

Thank you!