you can start at forex. They trade currencies (much like banks trade shares). I thought about buying some USD since my currency is so strong and will most likely drop. But didn't have the spare cash, or time to really look into it. It can be rewarding but you have to really know about the global financial state. A lot of reading the media and research is needed. Also look out for scams, i know there's a massive scam in australia where a company asks you to buy a 'package' for $1-5k and they you watch them trade and follow their every step to make crazy profit margins - load of garbage.