Originally Posted by
WorldLux
They are usually displayed in the options during the booking process. Probably ~5 to 10€/additional driver & day. Additional Young drivers adds another 5-10€/young driver & day to the additional drivers fee.
Well, all I can say is that in the last online rental place I was reading all the fine print, it said to check at the counter of the car rental place for the actual fee for an extra driver. Sometimes the fine print just doesn't have all the details you want (ironically, it did tell me how much the GPS and toll device rentals were

)
The IDP is not so much of an hassle to be honest. They can save you some time in traffic stops. I would say that they are worth their money.
As much of a hassle as a Chinese visa? No. More than a regular US driver's license? Yes. It's all relative. Biggest PITA for me now is I've lost my regular passport photo place

I had an IDL years and years ago and never used it and these days I HATE to rent a car when I travel overseas (and therefore tend to plan vacations where car rental isn't necessary)