Seriously do some searching on here I want to say the guys are paying around $200 for the OEM hitch kit at the dealer and installing their own.
Make sure the kit has all the relays you need,these may be additional.
I would guess paying about .5 to 1.0 hrs labor would be fair on top of the parts price.
$500 just seems a little too high,take this price quote(below) in and talk with the Svc Mgr(not the advisor) see if he will work on the price with you!
Note:the link below shows a complete kit with relays and the 7 pin connector,also in the link are the install instructions,look it over and decide if you want to do this or pay them to install for you.
Good luck and enjoy your new ride!
http://www.courtesyparts.com/Merchan...de=999T5-A6000