The dealer basicly charges what he can get for it. With the "employee discount" program that just finished, i was told that the sales margin was so small that they needed to up-sale anything they could.
I am offering the ValuGuard sealant right now for $179 including shop supplies. With all the new cars just sold, i do one a week with no advertising. I really should push it more as it is easy money. I do tell them the lowdown on such products, like expect 6-12 months out of them, alot of dealer hype etc.
Not sure if this is allowed but i do have a few bottles i would sell, as you have to buy in quantity. It is not cheap but i find i can do two cars per bottle. It is a weird product, as it disappears into the paint, you apply it and ask yourself where did it go, which is why i used more than i normally would.