Unless you're planning to raise very substantial amounts of money, advertising might not be the most effective tactic. It's worth perhaps playing with, but not doing more until you've seen it work. You're a small business. You've got a highly unsegmented market. In unsegmented markets, advertising is mostly about brand building. That works well if you're Coca-Cola, but much less well for small start-ups.

Word-of-mouth can work well, but you've got to understand your customers, the networks, and the levers you can tweak to change rate-of-growth. I was suggesting price/quality/margin as one of those levers -- you want to be appealing to as many customers within your customers' networks -- but there may be others if that one is unappealing.