So I’m looking for someone who can do the simple math that might help me decide whether to switch cars.

A little background…My SO and I live close enough to our work that we bike every day. We also live close enough to our local grocers and other “around town” needs, so we rarely use our car. Recently, however, I started graduate school, and my SO started his bachelor’s degree. This has required us to commute to the college in the next city over. The car we have is a rather thirsty Chevy Silverado. We only have the one car, and have kept it because it’s long been paid for and is convenient to have when friends/family have a once in a while truck hauling need.

With this new commute though, we’ve been thinking about trading it in for something smaller and more gas efficient, maybe a Prius or Honda CRZ that can get 35-40mpg. We’ve been trying to decide if it’s worth it, and just need someone to help out with the math…

So, the commute round trip is ~100miles. We will do the drive 14 times per month for 30 more months (after which we will both be done with school). The current car gets ~18mpg (ouch!). The new car would hopefully get 35 minimum (I’m taking suggestions on this too!). Gas here runs roughly $2.80/gallon at the moment. I have $10,000 in cash to devote to this without taking out a loan, although I would really prefer not to spend that much. We figure we could get maybe $4,000 out of the Chevy, but not too sure.

Any other variables I’m not thinking of? How cheap would a new car need to be to make this deal worth doing?

For the record, I looked into just moving to the city, but it looks like rent would double and in my line of work, I’d be taking a significant pay cut.