Home Based Business
There are many potential home based businesses that you can start for little or no upfront money. The first thing to consider is what you would like to do, and where your skills lie. If you're a computer person, perhaps freelance programming makes the most sense. If you're more of a people person, customer service via telephone support may be the way to go. Artists could very well find themselves pulled in the direction of graphic design or website building via CSS.
Once you've decided on your home based business, the next step is getting the word out there that you are available for hire. This can definitely be done online, by setting up a website, posting your information on forums and job boards, and using social networking such as Facebook, Twitter, and other applications.
To have the most success, however, it's likely that making an effort in advertising offline (namely, in the real world) will lead to even more business and be an investment worth taking. After all, the internet is a big place and you want to do your very best to get noticed by all potential customers.