How can I start my business in internet & the web without investment.

What kind of business? It is obvious that if you need an inventory, you need to spend money.

What kind of business are you looking to start? If it's a website-oriented business, you're going to need to learn some coding fundamentals so you can code it yourself (which is one way to start your business without an investment) or you can hire/out-source the development for a small price. Some more information could help in deciding what options are available to you.