Promote a product or service online as an affiliate. Lots of companies have affiliate programs. Make some searches to find a company that sells something you're interested in and find out if they have an affiliate program. Then sign up. Most companies that have affiliate programs will provide you with sales materials you can use. Some even show you how to advertise online. Don't pay for advertising, at least not at first. There are lots of ways you can advertise online for free. One way is called "bum marketing". Do a search for the keywords "bum marketing" to learn more.