1.You won't know who. You don't need to. And probably nobody will be able to tell you. But, weel: Just think it's other poeple like you.
2. I guess .50 cents is per option contracts. Buy/Sell stock orders are charged between $7 to $20 on online brokers (except Zecco which is free, lol).
3. If You can make a profit in one minute, good. But that's not the way it works.
First you search, compare, analyse many companies and their stock evolution and eventualy buy one. Then you watch the stock price move day by day (or so) and 6 months later you will decide it's time to sell (or to buy more).
Welcome to stock trading/investing.