try reading Kyosaki's Rich Dad Poor Dad, it's about creating passive income...
...and if you like it, then read Benjamin Graham - The Intelligent Investor twice...
Do really well in school, get a student loan. Use student loan for side business while living at home and going to university. Lowest interest cash you are going to have access to your whole life.
I would say the lowest risk way to make money online is SEO... you can pretty much do SEO with just knowledge and sweat equity alone while spending little money up front. If you do a good job and get some good rankings you ll see a very good ROI on your up front time. The downfall is you won't always succeed and you will end up sinking alot of time doing boring ass tasks for projects that don't pan out.