Actualy there is no limit of how much you want to trade it depends on you as long as you can afford to lose. I my best starting capital with trading is around 100$ but you can also start trading even in a lower capital and you can start a big capital when you already good in trading.
Before investing in this market, you should first learn. But the learning should be accompanied by the practice is so effective so with the $ 100 capital to practice I think reasonable.