MSN Money has a pretty good article on how to prevent wasting money on your car. Here are some of my personal recommendations:
- Get your oil changed with synthetic, use a premium filter, and only change your oil 1-2 times per year depending on usage. You can run a car that's lubricated with synthetic oil for a couple of hundred miles even after the oil has been drained.
- Go buy a K&N air filter. Chances are good that the air filter will last longer than the car -- just hose the thing off every so often and let it dry before you put it back in. For better performance use the K&N cleaning and lubrication kit.
- Think hard about extended warranties for 4WD vehicles. My general experience has been that you start having seal leaks somewhere between 50K and 75K miles and costs for seal replacements can go right up in to the thousands. Consider how long you'll keep the vehicle and how aggressive you'll drive the vehicle before investing.