For small business owners, what was your best marketing strategy to attract

leads/prospective clients? I have founded a services-only company that is about to go live into public markets. Our last motion before we open doors is our marketing strategy. We are a guerilla company that needs to operate off of having low overhead, low start-up costs, and low fixed expenses. Thus, our marketing strategy must be relatively cheap, but effective. I've gotten into social marketing, and have thought about mass mailing or door hangers throughout various neighborhoods. What marketing strategies best worked for you in attracting clients from the moment you opened doors for business? And how much did it cost for you to carry out this strategy?