9qts of Mobil1 sounds right. It's about $5/qt. retail.

A good independent can do all the same maintenance and likely save you some money. You can also do it yourself and save lots of money if you're inclined to do so. The schedule A & B tasks are well documented on this forum.

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1998 E320 120K mi
1991 Miata 80K mi
2001 Ranger 109K mi