I personally think Social Media pages, including sites such as Alignable are the most effective both in reach and cost.  With a small business, word of mouth is also very important.  Sometimes, offering satisfied customers a referral bonus for sending other clients your way is enough of a carrot to get more people in the door, creating more satisfied client....and on it goes.  Good luck, and try to stay current  on Social Media.  They are a great way to advertise for next to nothing...usually just someone's time.