Use your car less.
We made two excursions to the grocery store on foot recently. It helps that it’s only a quarter mile one way. This is obviously something easier to do if you live in a dense city or neighborhood. We also try to eat and shop at places that are closer to our house to minimize driving and encourage us to walk or ride our bikes.
We’ve [read: I’ve] learned to do less shopping generally, so that helps to minimize the number of times we drive around the city.
Cost: Less money on gas. More time as driving is usually faster. However when you walk or bike, you get some exercise time in with your errands.