There are many ways that people today make money online. One that you are probably familiar with at a basic level is eBay. Many people purchase items they find in clearance racks at wholesale or lower prices, and then let the bidding wars on eBay earn them a decent income working from home. Of course, if you want to do this you will have to spend some time outside your home learning the best places and methods to obtain items cheap. Which, is kind of the point of eBay, but there are people who make money online quite well this way.
You also might consider selling your skills to make money online. What this means is that you find projects from people who need your skills, and complete them in exchange for money. There are a wide variety of websites where freelancers can meet with clients to make money online by accepting projects or bidding on projects they have the skills to complete. This is true of everyone from web programmers, designers, and even writers. Basically, if you have a skill there is probably a way to market it so that you can make money online and be working from home at the same time.
However, one thing you have to remember is that no matter which way you choose to make money online, nothing will work for you unless you have a strong will and work ethic. There are no easy shortcuts to make money online, so if you want to start working from home you will need focus and time management skills.