cost to drive to Bahrain (Riyadh)

Can someone please tell me what the going rate is - or the range - for hiring a driver to take one person from Riyadh to Bahrain?
I would like to go on Thursday morning, and I have a possible driver, but he is asking what I want to pay (this is an annoying question, cause I don't want to pay anything, really). I would like it to be less than a one way plane ticket, but what is reasonable?

-Shelagh