RAC Auto

Okay, so I’m driving along Manning Road, heading towards my friend’s in Bentley and suddenly, at a red traffic light, my car stalls. And just won’t start up again. I try several times clicking over the ignition then have to put my hazard lights on and irritate a dozen or so drivers who have to overtake me. Stuck. At a red-​now-​green-​now-​red-​now-​green-​again traffic light.
Anyway, I call my friend, he tells me there’s an RAC just around the corner on Albany Highway. I don’t believe me. It’s true, he says. With a major prayer to the gods, I finally get the motor kicking over but have to drive over 50kms at all times (ie: NO slowing down) so as not to have the vehicle stall on me.
Anyway, just as I get into the RAC carpark, the auto conks. The guys come out and I tell them of my situation. I also tell them I was going to join that very afternoon but am not currently a member. No problems. They pointed me to a public phone to make a quick call to join for a hundred bucks. Excellent. And now I don’t have to pay for the checkup they do on the vehicle.
Anyway they recommended a new voltage regulator and assessment of the vehicle. Their quote for this $ 350. I checked around and found that a new VR can cost around $ 130 so what’s with the hike in price?
I think it’s great that the RAC allowed me to join on the spot and waived my consultation fee, but I wonder why their part replacement, in this example, is twice the price as smaller, commercial service dealers?