I agree with affiliate/finder fees as will bring you a lot of word of mouth promotions and recommendations. Sometimes I think it pays to get down The Strand or whatever with a massive advertising board and get in the background of a live TV news broadcast. Or stick a big advert on the side of the van and stop just behind them (probably need a portable TV to get perfect accuracy)... the cars beeping away behind with get viewers attention (and likely the journalist too). Never tried it but its on my list of things to do. As for a driving school, courier etc. where you have advertising on the side of your vehicle... use that!