Here's a typical dealer story:
I went in awhile back looking to stock up on the discontinued non-resistor Bosch plugs for my 103 motor.
Parts guy said he had 18, at $6.75 apiece.
I said if he could give me a discount I would buy all 18.
He immediately said "Well, okay, I can go $2.25 each".

Maybe I should try that on a new S-Class - HeHeHe.

Of course, I later found a couple of boxes of plugs at Napa, for their std price of $1.07.

DG