Fuel Mileage Experiment, Week 1

I'm conducting a fuel mileage experiment for the next couple of weeks; in fact, I just finished the first week. Here is the experiment: At the start of week one, I will fill up the gas tank, then drive conservatively everywhere I go. No speeding, and no jackrabbit starts. Then I'll record the mileage, refill the tank, and drive like I normally do.

So week one is over. Here's the results:
Mileage: 262.8 miles
Gasoline Used: 9.046 G
Miles per gallon: 29.05

Assuming a price of $4/gallon for gas (which is a bit low but pretty close), that means it cost me $36.18 to drive those 262.8 miles, for a cost of 13.77 cents per mile.

Also, the average time to work (23.3 miles) is about 25 minutes, versus about 22 normally. So I'm saving about 1/2 hour of time per week driving my normal way. How much am I paying for that 1/2 hour? We'll find out next week.