$0. If you have to ask what amount you should start with, then you do not know enough about trading to profit. You should continue to learn about trading strategies and analysis (it should take you more that a month before you reach step two). Once you know EVERYTHING about strategy, analysis, and trading algorithms, then it is time to move onto step two: Paper trading. Paper trading is when you look at the exchange price and write down your trades on a piece of paper (at the market price) WITHOUT actually purchasing the trade. This is a crucial step as it is how you will work out the kinks in your strategy without losing money (you should spend at least another 2 months on this process). Finally, it is time to trade! At this point you already know the optimal amount of capital for YOU to trade- because you know EVERYTHING about trading .

Good luck and DO NOT rush this process!