When you sign up with Google to use AdWords, you enter criteria for your ad, such as target market area (e.g., your city), and your budget for each month. You are only charge when someone clicks on your ad.
When you get more advanced at using AdWords, you can target the ads at specific things, like Christmas or Weddings.
I signed up for Google AdWords back in February, and for many months wondered if it was working for me. I had a few inquiries the first few months, but not a lot of jobs coming from Adwords.
That has all started to turn around the last few weeks. Recently, I have had 3 wedding inquiries and 2 portrait inquires through AdWords. Business is definitely picking up! Based on the recent success, I will probably increase my limited budget on AdWords up a bit. This will help the ads to run more often during the month.
I will post an update later in the year to let you know how the ad campagn is doing!