Want to freelance and offer your services from the comfort of your own home and computer?  You must have the ability to network yourself and get the word out about your abilities.  You must also have a good portfolio.  Prospective clients will want to look at examples of your work.  Some clients will be more strict about their demands (contracts) while others will be more word of mouth.  Keep track of all correspondence whatever you do and you may want to consider using contracts (to be safe).

Freelancing can bring in extra income for you as you continue to build your portfolio and reputation.  You can gain more credibility and recognition by getting your work "out there" in the real world.  You can add who you've 'worked for' to your resume. 

There is a lot of competition out there so make sure you are ready to fulfill a client's desire's as an effective designer-capable to take on a certain level of project.  As a designer you should be versatile in your skills so you can appeal to a wider range of clients.  You can build a portfolio on your own and then when you're ready you can start freelancing.