When Catherine Wood Hill co-founded an online fashion company for plus-size women, she devoted the bulk of her marketing budget to Google AdWords. The result: She spent almost $14,000 in one month to close $3,838 in sales. A PR consultant and a big e-mail list didn't perform any better. Today, Hill focuses almost entirely on search engine optimization, plus Twitter and Facebook. Last month, her sales were $6,053 -- on a $30 marketing budget.