So, how much should a first service cost (aka Dealer BS???)

[samhkang]

yeah, my rear break squeaks too and everyone here told me that's normal for GS500. I just live with it.
Another thing that is common with GS500 is that when you come to a stop, sometimes you can't get into 1st gear from Neutral. If that happens to you, just let go the clutch all the way(while in the neutral) than pull/sqeeze the clutch again as you kick into 1st gear. This is called double clutch technique and it works great.  Others use rolling back and forth method but I think the double clutching is alot quicker and easier to do. BTW, I did my first service myself not worring about the valve. Pretty much tightened everything and did the oil change. The bike still runs great.