Question: Karen asked "Hi, do I have to do anything or is it free?"
Yes, you do have to do something to get started - but, if you take the time to learn you should be able to do it.
The basic concept is to either create your own informational product on anything (such as an ebook) - or, sell someone elses product and earn affiliate (or a portion of ) the sales. As for up front costs - the guides that I'm promoting are all very inexpensive and explain the process well. But, you certainly don't have to buy all of them to get started. Holly Mann's guide is in my mind the best one out there and really explains just what you have to do technically to get started: Honest Riches
As with anything you do - to make money online takes time and dedication. The real secret to the online formula is your own knowledge and passions - because you get the benefit of others promoting your own ebook or product. Take a look at my free online guide about how to start thinking about online marketing. This is all about how to start before just jumping in and is completely free for you. Get it here: Passions to Profits - a FREE eBook
Plus, take a look at my blog post:
What is the Best Method to Make Some Money Online?
This was in answer to a Yahoo Answers question that might help you. It talks specifically to the pitfalls of this business and what you should do to try and make it - read it carefully - the points in the post are the #1 reasons people fail online. Not every idea is a winner - sometimes it is a mix of the right product at the right time. But, if you have passion and show it - you should succeed.
Remember, that to truly make enough to quit your job will take serious investment on your part - education, passion and time. Not many can get to that point - but, at a minimum you can make some extra money if you do this. Don't rush into anything - especially anything costing more than $100 - if it sounds too good to be true, it most likely is. One beginner's guide has every step you need to know. Learn from how others do it. I hope each of those links help you.