Legitimate broker for a beginner

I am from Sri Lanka.
I am still learning and in the mean time looking out for a legitimate broker which are suitable for beginners as I am planning to invest about USD 100/150.
Can you suggest a suitable legitimate broker and at the same what would be suitable leverage and lot size I should select. As of my learning, I believe to use 50:1 leverage and use micro lot as my invest is also a small and target in the currency pairs EUR/USD, GBP/USD & USD/JPY…
All your experience and knowledge sharing are most welcome…