Stocks are bought and sold on stock exchanges. But be careful, you want to stick to well known, credible stock exchanges like: -The New York Stock Exchange -NASDAQ -London Stock Exchange Group -Euronext -Toronto Stock Exchange -Tokyo Stock Exchange Avoid: -Pink Sheets
It really boils down to supply and demand. When supply is high, price goes down. When demand is high, price goes up. Pay attention to the bid-ask spread. If it looks wide, odds are sellers are asking for alot more than buyers are willing to buy it for. You gotta ask yourself why is that. Always do a fundamental analysis to make sure you're buying the right stock for the right price for you.
You won't make or lose money until you go to sell the stock. Up to that, it's just the value of the stock that goes up and down. Buy stocks that you want to hold for at least five years. When you're ready to cash in on the profits, you sell it and make money.