Hi Jessica,
Sorry to hear that you're feeling discouraged. What other methods of marketing are you using? How long have you been in business?
I have been in business since April 2008. It took me 3 months before I got my first client (off of Craigslists coincidentally). I utilize several other marketing strategies such as direct mailings, forum participation, attending networking events and work hard to get decent traffic to my website. I have gotten several leads form Craigslist, but only one client.
I've had my posts flagged previously on Craigslist for using the word "Virtual Assistant". Perhaps it's the moderator in my area or someone flagged me, but I see a ton of other VA's post Virtual Assistance Services on Craigslist.
My point is, I have found only a small benefit from Craigslist. I would never put all of my eggs in one basket. I also know regular clientele takes a very long time to build. (MY SBA counsoler told me it takes 3 years!) It requires patience and motivation.
I know the experiences on sites like guru and/or Elance have been
reported to be more good than bad, but in desperate measures, working for pennies may be worth it if it puts a meal on the table or keeps the heat on.
Keep checking the RFPs and Services Required here on VAF.
Really dig into this
general marketing portion of VAF and come up with a fresh list of ideas and tactics. Take your lemons and make lemonade. Take your feelings of discouragement and turn them into focus and determination.

The possibility of being successful is there. It's up to you to make it happen.
Best wishes,
Dawn