I agree it is a lot of money for changing the brake fluid and I don't want sound like the devil advocate but, that brake pressure bleeder costs $3000 with a couple of adapters (and it doesn't last forever). I know it because I bought one. I know it is a business investment, but I too cannot charge just a 1/2 hour labour for changing the brake fluid plus the fluid. I use ATE SL6 ESP brake fluid and it is not cheap. I'm guessing that VW dealers would use the same fluid.
But, shop around and you should find the place when they will change the fluid for less. :)
http://www.vwwatercooled.com.au/foru...46ee84_b-1.jpg