I work out, shower, eat, charge all my batteries, use the internet, etc at work, and then park overnight on Shoreline, so there is essentially zero cost of living.
Im not counting the cost of things I would still be paying for if I lived in my cupertino apartment though, so like gas, car insurance, car maintenance, health insurance, laundry, etc.
I think my one cost would be about $10 worth of bulk silica desiccant every month to keep the moisture in the car under control while I sleep in it.