One of my guys is extremely clever. He paid for a car wash membership at a VERY busy gas station on the corner of a major artery here in town. Every morning his team is out there washing and detailing the van... and everyone sitting in traffic gets his number off the side of it in the process, since they're stuck at a red light and have nothing better to do. The phone starts ringing before the boys have even finished drying the van. He hasn't paid for a single day of advertising beyond that.
I love that! I live in NYC so things around here are pretty tough, so much competition. I often feel I would do much better in a small town. Nonetheless, I put a lot of effort in Google SEO and have had some success. Adwords works, not great, but it works