Join Freecycle, where you can give away what you don't need and get second-hand stuff for free.
When the activity is fun, good for the environment, and also affects personal health (physically and also psychologically), it's much easier to maintain. So if you like biking, bike. If you like cooking, cook local.
Never use your car for a trip of less than two miles. Walk or bike. Notice the benefits to your physical fitness.