TOYOTA likes to think of its quirky, boxy Scion as a 21st-century chariot of the soul — not just an affordable car, but also a unique expression of the young, hip person who Toyota hopes is driving it.

Now Toyota’s Scion enthusiasts will have even more “me time”: a marketing campaign with an underground vibe that is intended to show just how much their chosen transportation reflects their personality.

With an eye to the social networking ethos that has made Facebook and MySpace wildly popular, Toyota will let Scion owners design their own personal “coat of arms” online, a piece of owner-generated art that is meant to reflect their job, hobbies and — um, O.K. — karma.

In making their personalized crests, Scion owners can choose from among hundreds of symbols, all designed by a professional graffiti artist. The symbols range from an eagle, a jester, a king’s crown and a worker’s fist to Japanese anime-style flowers, a three-person family and a yin-yang circle. Customers can download their designs and have them made into window decals or take them to an auto airbrushing shop to have them professionally painted onto their cars.

The Scion is an economy car aimed at younger, stylish drivers, and the design Web site, scionspeak.com, is free. But Scion enthusiasts must pay for the auto shop renderings of their design, an indulgence that can cost thousands of dollars.