The cheapest route through the local German dealer would be to bring all of your own fluids, purchased from AAFES, with a VAT form.
I did my own initial service for the ultimate in "cost-effectiveness". I do have a contact that can get my service in to the system and have the service book "pre-stamped" for convenience.
I am trying think if there is anything I can plan ahead for as I head to CONUS for a TDY next week....