I'm not too sure about your exact field, but I have been a consultant since 1995. The only things I pay for is a computer, business cards, a website, and any networking meetings or conferences I attend. That is the beauty of consulting or coaching, you can literally start with almost zero financial investment. The main investment is your time and energy marketing yourself.
I would recommend researching other people in your field. Try to find them online. See what they are up to, where they hang out. This will give you an idea of what might be required of you.
To find clients, contact previous contacts at any jobs you might have had.
You could also try posting your resume on guru.com, LinkedIn and Craigslist and other types of sites. I know many people look to these sites when they are looking for writers in a certain field.