Excellent point Joanne!
Be a resource for people, not a salesperson. I have found that there are many effective free ways to promote on the internet. iContact is a very effective resource as Joanne noted earlier, my whole team uses the site as well. I have also found that free online ad placement, if consistent can produce excellent results for you. Places like Craigslist and Kijiji, if not abused, are great places to get exposure.
Note: Consistency is key with this. Just like people need to trust you before they decide to join you in business, I believe the same psychology applies to ads. People need to see them a few times before they open them... not all people, but it seems to be what I have found. I hope this helps!
