Depends where you are in the world,here in the UK 45 to 65 pounds, dealer 150, when they plug in it will tell you everything that has a module connected to it,some of the modules will not respond, this is because you dont have that bit fitted to your car and yes they can also reset the air bag light.
Also get them to erase the adaptions on the engine and gearbox, what this does is get rid of the memory basically,as the car has learnt how other people have driven it and adapted to there driving patterns, so with it erased the car will learn how you drive.
VELVET BLUE UK INDIVIDUAL , IM THE LAST
UNITED WE STAND DIVIDED WE FALL
I stepped in a plate of Pasta the other day - now I have to worry about my Carbonara footprint!