best ways to earn legal money in the internet?

I'd second e-commerce and also affiliate marketing.

Selling high quality products at a good price is most reliable way to build a solid income stream. Affiliate marketing is good, in that you don't need to develop your own product to sell, and instead can focus your full efforts on just selling and marketing.

Once you're comfortable with that, you can start developing your own products and capturing even a bigger portion of profits once you sell them.