A trader who expects a stock's price to increase can buy a call option to purchase the stock at a fixed price ("strike price") at a later date, rather than purchase the stock outright.The cash outlay on the option is the premium. The trader would have no obligation to buy the stock, but only has the right to do so at or before the expiration date. What this means is, if Pfizer falls anywhere below $25 before the third Friday in October, you can sell the stock for more than its market value. Options are no longer just for large Day trading markets such as stocks, futures, forex, and options have three separate prices that update in real-time when the markets are open: the bid price, the ask price, and the last price. They provide important and current pricing information for the market in question.