My dealer charges 9.50 a quart for Mobil 1. I can get it a lot less at Wal-mart. I'm starting to use Amsoil. Just got in my current change and filter for 67 bucks and the dealer won't charge too much to put it in. Gave up doing that work long ago. The Amsoil is supposed to be good for 25,000 miles, doubt I'll wait that long, but never know. CR did a report many years ago in NY taxis and changed at 3,000, 5,000 and 7,500 and there were no differences after 100,000 miles at tear down so I'm not too religious about a short cycle on the oil.
Anyways, not too surprised about how expensive the change was given the excessive dealer markup.
2004 QuickSilver GTO