Great advice from Vivid. It doesn't have to cost money but if you want to go down this route do trial it first & see what works best for your business.
I have seen Facebook & Twitter generate leads & I plan to go into business in the not too distant future in this field, BUT agree that you have to integrate any use of social media as part of your overall marketing plan and approach it with a targeted strategy in order to achieve the outcomes you want eg engage with your existing followers, increase likes, drive people to your website etc
PM me if you want any advice.