You don't mean the stockmarket, this is for stocks and shares. You mean FX market. This is done with electronic money, not physical money (that's for holidays). You will find the spread and/or charges will outweigh any profitable movement in the exchange rate. Think again.

That's not the stock market - that is currency speculation.

Like if you have euros exchanging it for dollars re-exchanging when you can make a profit... I have 500