Get your Green Oil for free (G-Oil).

There's a really cool oil and cleaning product company that produces bio-oils and cleaning products from plant and animal byproducts. Animal fats seem to be a big part of the oil. It has a patent pending technology using nanotechnology that they describe as: "superior performing ULTIMATE BIODEGRADABLE* motor oil made with American grown base oils and the power of nanotechnology to reduce wear, lower friction and provide more horsepower while being safe for the environment."

Seems to be fully compliant with vehicle guidelines for oil, so you won't void vehicle warranty or have other issues.

You can get a refund coupon for the the oil required for an oil change at: http://www.getG.com/CAarAndDriver 

Sold at Wal-Mart so it should be possible to have them use G-Oil if you don't want to change your own oil.