Actually I think $47.50 is very reasonable for an oil change at the Lexus dealer.
You have to think about the source. You can't expect Nordstrom to charge the same for a pair of socks as Wal-mart would...even if they are the same socks. Nordstrom spends more money on decor, location, comfort, training their staff, paying their staff who tend to be more experienced in customer service. Totally different operations.
As it is for the Lexus vs Toyota dealer.
For the Lexus dealer to run their operation with all the additional overhead they probably have the same profit margin on that oil change as the Toyota dealer.
Here's my $0.02: "A penny saved is a penny earned." I understand your rationale, but I disagree. I can't justify spending almost 3 times as much at a Lexus dealer for the identical service from a Toyota dealer - it would be different if Lexus wasn't Toyota, but they're the same corporate entity. The Lexus "amenities" are nice - Starbucks coffee, USA Today, PC access, HDTV - but since I already had them before I left home, they're worth zip to me. Plus, my Toyota dealer is more convenient, being much closer to my home. The Lexus service might be worth a 25 or 30 percent upcharge, but 267%? Not in today's economy. If Lexus is to survive on their non-warranty service, they need to be more realistic and competitive.