Car maintenance: Don't skip these 8 moves
Changing fuel and air filters
CarMD's Brocoff says replacing a dirty air filter can cost as little as $20, but if you neglect to replace it, this can cause an oxygen-sensor failure that will cost as much as $250 to repair. Ignoring that needed repair will reduce your gas mileage, which will cost you even more money.
Eventually, the car could misfire, and you'll end up spending $1,000 or more to replace your catalytic converter.
"You can buy filters and other parts online," Woroch says. "Be sure to read the reviews to evaluate whether you or a mechanically inclined friend can handle the repair on your own."