yes of course 'cause no one will risk money if doing investment can't multiply money simple as that.  And by the way talking about how much money require to invest then the answer is its up to you if you can afford it but always note that doing investment is very risky so must buy what amount you can afford to lose and also don't forget to don't put your all eggs in one basket to save your money incase when the market suddenly turn to red for long time like nowadays.