Yes, it's an anathema to many business people, but the fact remains: giving something away for free can be the best way to attract future customers.
I saw this again in action at a recent regional tourism marketing conference I was speaking at.
There was a relatively new massage/health spa in the area and they were at the conference giving massages at breaks to attendees. The two owners were there in branded outfits. They covered all the accomodation owners and, importantly, the MC for the day, Lawrence Mooney from Postcards. So they took the opportunity to let important prospectiver referers "sample" their service free of charge - which will translate to referrals and perhaps even a spot on tv should Postcards ever cover the region. Plus they got to attend the conference, network and learn from the various presenters. What a smart zero budget marketing tip put into action!