Point of interest... the po changed the oil for me at the dealer just before I bought the car. The dealer put in 5-40 Penzoil synthetic and a sticker to have it changed in 3000 miles.
My local Chrysler dealer has a sign on the wall that their labor rate is $110 an hour!!! That's more than jet airplane mechanics charge.

I buy my oil at CostCo when I see specials and just hang on to it.