This one can make millions, but the condition is you have to be creative and unique. If you are good at words there is a blog. If you are good at video there is youtube. You can even sell you graphics printed tshirt without any single dollar investment. However most of Internet users know these options, but they might afraid to start.
Sweepstakes & Giveaways
Brands are spending billions of $ for customer retention and awareness. Some companies are grown just by sweepstakes and giveaway only. They regularly gives cash, holidays, event tickets and even cars. All you need to do is visit websites like sweepstakes bible to get regular update of such contests and sweepstakes. You can participate according to rules and regulation. There no any purchase necessary in such giveaways.
There are various sites like Shopify.com allow you to sell products online. You don’t need to stock, purchase or even see the product in hand. You need to market it. They manage your order and customer care. All you need to have is ideas to bring customers to your website.
If you are expert in anything, you can provide your service and earn money with extra time. There are lots of service like, website , graphics, contents, SEO, translation, electronics design, project consulting, online tutoring, video production, dubbing and many more. There various freelancer network where you can search such jobs. You can also post your offers in fiverr.com
These assets are not like tangible assets, it can makes you millionaire if you understand the market. Online assets like domain, running website, ecommerce website, youtube channel, mobile app and many such properties can be bought and sold. Some people only develop such assets for few year and sell them at good prices.
Start-up & Ideas
If you belive in some idea and work on it, It will give great rewards with time. All you need to have a amazing and unique idea or solution. Most of the current digital brands are born with such small ideas. If you can bring change in market, you will easily get more funds to grow and grow.