What has been your smartest investment?

My husband and I set our hearts on having our wedding at a beautiful inn on the Hudson River, but we couldn't afford to book it. We're musicians, so we spent $900 on sound equipment and set out on what we called our Wedding Tour, playing acoustic sets at any venue that would hire us. We were able to pay for the inn six months after the tour, and in the 10 years that we've been married, we have exceeded every financial goal we've ever set for ourselves.
This tip comes from Real Simple reader ANN BYRNE, Wappingers Falls, New York