Bottom line – before you start spending money on marketing use your head. It costs only your time and brainsmarts. And some minimal site customization (paste some code here, put a widget there, setup a custom promotion somewhere else).
When you start a business you know nothing. In fact you know less then nothing about your target market since you have your assumptions which might take you in the wrong direction. And there are lots of technology-savvy advisors selling you their technology taking your time which you should spend on your business.