1: Start up a home based business by selling things on E-bay. You could buy wholesale and sell for higher on E-bay, or you can sell your own personal things that are of no use to you. Learn the tips and tricks of how to effectively sell on E-bay and how to maximize your profits.
2: Research a topic that people today want information for, and are willing to pay for it. Write an e-book or a report that contains the information that the people are looking for, and then sell it.
3: Buy or otherwise obtain private label rights products/articles/books/etc. You can do whatever you please with these. You can rewrite the books to your own style and resell it for 100% profit. One thing you can do with PLR articles is compile them into a single book, and then sell it.
4: Start up your own online store. More and more people are buying things online, so you could cash in on this. What exactly would you like to sell and to who would you sell it to?
5: This is a popular one: join an affiliate program, and start up an affiliate marketing business. Instead of selling your own products, you sell other people's products and earn commissions when you're successful. This is great if you're not creative enough to create your own product.