I have been using PPC effectively for the last few months and the key is to use long tail keywords to get cheap traffic. Use the keyword tool in google or if you want to take it more seriously I highly recommend Wordze.com or keywordelite.com for your keyword research.
Both excellent for finding thousands of keywords in your market.
I would go with submitting articles to ezine articles as well if you don't have a budget or any relationships in your market. Always works well for me when I'm starting a site and want some free traffic fast.