Even if you don't do they change yourself, I'd still recommend purchasing Mobil 1 oil wherever you find on sale-- and buying a good discounted aftermarket filter (like the Bosch 3300). Kragen periodically has the 3300 on sale at a great price (...and permits you to purchase 3 or 4 at-a-time, at their sale price.) A genuine bargain...
Many garages will allow you to provide your own parts--you'll obviously pay labor, tax and hazmat fees. I'd call around to a couple of your local SF garages--you'll likely find one that will accomodate you.