stock stuff ..no idea @ all..but still wanna learn ..some day have to be millonaire.. here is the quesiton.. 1,  let's say  i  have created brokerage account..minimum accnt balance 500 bucks..so far my understanding is i can use only the money deposited  beyond 500 bucks for trade as minimum amount on my account should be 500 buck..m i right? or as usual i m understanding something dfferent.. 2. ok i buy 4 number of stock  of apples, each  for 500 bucks..total  at 2000 (can't buy millons of stocks now.may be in future). where to buy these stocks by the way..online...??? .ok luckicly next day the price for one stock reaches to 600 bucls(competition with google) ok i have 100 bucks profit on each..total is 400 bucks..enough to hang out for some days?? so how i m gonna trade that..online?? does  the stock value changes everyday or every hours.. how broker makes profit and what role they play.. ok enough questions..waiting for reliable ans.. thanks in advance