how can i get rich?

There is no one answer to this, but with your scheme your looking at, the best route for you would be to get a job at a super market or something and earn an initial investment; From there you could then progress on to researching what sells (Phones, Microwaves or simpler stuff like clothes or broken laptops in joblots) from there find a platform to market yourself on; A key point is, you won't be self sustaining for a while and building a company like this takes time, money and hardwork. Don't aim for loads of profit from one item, aim to earn what you brought it for including platform fees and shipping + 5, not alot for one object but the greater picture of things then creates large amount of profits for you to invest.

Tl;dr: Earn an investment, Research items, Find a platform (eBay, Gearbest, etc), Sell item for an amount that covers price, shipping plus 5 (or less) profit, Repeat, Profit?