The minimum capital that is required to trade effectively and compound profit is 50$; anything below that means that you are literally wasting your own calls, signals; because without a good capital; the only way to make money is if you are making over 100% profit which is not sustainable. Your profit is someone else trade capital; so i implore us to twice your trading capital.
And once again, if you are to scared to loose money; then don't trade, it is not for you
For a beginner, low amount of capital is okay because they don't have experience and enough knowledge on trading. With small amount, they will be able to learn trading properly. But for a professional person, $50 is not a good amount of money for trading.