said 1 year, 5 months ago:
Share quality content. Engage like crazy.
These are the two things that I do to promote my copywriting service on social media.
I am subscribed to hundreds of RSS feeds on topics of interest. This is how I keep myself updated with developments in my niche. It is also where I get ideas on what to write about. I write content for my own blog at least twice a week.
I have a number of social media accounts. I share content with these accounts at least once a day. Everything points back to my blog, where you will find my sales funnel.
Always on engage-mode
The majority of my time is spent joining conversations. I comment on blogs with commentluv plugins, I join forum like these, and I interact with people and pages on facebook, as well as other social media sites.
The intention is not to spam, but to offer solutions and build rapport. I never sell them anything. What I want to happen is for them to come to the conclusion that I was able to help them with their problem. No strings attached.
As you can see, these activities will not cost you anything but your time and effort. Soon as you start getting more business, you can choose to outsource these activities, or scale them down to manageable levels.