OK this happened to me with my 2001 300RX. First time I had the dealer install the front plate directly onto
the bumper during a routine service. If they charged me it was really minimal, like $10.
They screwed the plate directly to the bumper, with no mounting bracket. After about a year
the plate started to fall off because it was not that well secured. The plate was literally screwed onto the bumper.
I asked them to put it back on, more securely, during another routine service. Well, this time they put it
on with one of their own "dealer" licenseplate brackets that displays the name of the dealer. They did
not charge me for this. However I noticed that they also replaced my regular rear dealer bracket with one
of their own as well. I originally bought the car on the east coast and had been driving it around with a rear east coast
dealer bracket, while in southern CA. Now I have two matching "santa monica lexus" dealer brackets.
I assumed they did it for free because it was free advertising for the santa monica dealer. I did not ask
them to replace the rear bracket but lo and behold it was replaced when I went and picked up the car.
So far the front plate is fine, it seems to be stuck on the front bumper OK since they reattached it with the bracket.
I'm not sure where you are having your car serviced, but that sounds they are trying to rip you off by charging
you so much to fix this.
Bottom line - the dealer should fix this and they should not be charging you so much for it. I believe my service
dept has done well by me in this regard and I really did not care what dealer name was displayed around the plate.
p.s. I was already having other work done when I brought it in. Not sure how much it would have cost if I just brought it in for the plate.
p.p.s. I too got a ticket and the police said to take it to the dealer and have it fixed.