Use a zero-based budget. This means that each dollar has a "place." If you have $300.00 left over after all your bills are paid each month, use the envelope system to put that "extra" money aside. I have several envelopes for various savings (i.e car repairs, vacation, clothing for kids, date nights, etc.) and the amount I put in those envelopes depends on the need, so obviously I would put more in the "car repair" envelope than in the "clothing" envelope, just so that I'm not hit with a huge expense if something should happen to my vehicle.