If you are looking to break into this business it is possible with a few websites that offer designers a chance to get known. Take for example:
99 Design is a great site. You will join the site and post your designs. If you are selected the money is awarded to you. People go to the site looking for logs, new graphic designs for their business signs and many other things. You could do an ad campaign or even a poster. This all depends on what a client wants.
There are several other sites that allow graphic designers to join their site and enter into competitions to compete for the rewards that are offered for the best design.
Client post competition and describe what they are looking for. You'll enter your design and the person who created the contest will choose the winner. Your earnings will be based on how much the client has paid.
There are also many greeting card companies who are looking for a fresh new idea for their card line. You can try a few of them and submit your idea. They pay rather well for your design they use. I believe that you can earn up to $100 for each design the company buys from you.
You can also advertise your talents on Fiverr or Tenerr to offer your work to anyone who is interested. Many new designers will do this. It is difficult to be a freelancer at first, but once you build up your clients the amount of money you can earn is endless.