Where is the best place for Web Designers to advertise?

Google Adwords is the way to go. People think it is expensive, but if you set up your PPC campaign correctly it doesn't necessarily have to break the bank. Another viable option is Facebook marketing. They have more customization options as opposed to Adwords, allowing you to narrow down your target demographic a bit more. There many companies around the world that specialize in online marketing and PPC advertising. You might want to look into hiring out. I have had some success in the past with http://www.seoinfluence.com/, but my niche was not nearly as competitive as web design. Good luck my friend.

Google adwords may be a little expensive but it will bring in many leads

You could do with joining a business based forum. Become an active member with a good reputation. Don't spam but make sure your signature is to your website and try to find topics that are related to website designing. Most businesses like to own a website! Here's a Google search to get you started: http://www.google.co.uk/search?q=business+forums&sourceid=ie7&rls=com.microsoft:en-gb:IE-Address&ie=&oe=&redir_esc=&ei=e3R7TpfNJOjL0QWgveijAw Secondly, join a forum for the software you use to create the websites. If you can give really helpful answers to support posts, people will notice that you are quite handy with software and can make really good websites. It will build on your business' reputation too. I'm a website designer too and forums have always worked for me!