If you are buying an option that is already "in the money" (meaning the option will immediately be in profit), its premium will have an extra cost because you can sell it immediately for a profit. On the other hand, if you have an option that is "at the money," the option is equal to the current stock price. And, as you may have guessed, an option that is "out of the money" is one that won't have additional value because it is currently not in profit.
An option is a contract that allows (but doesn't require) an investor to buy or sell an underlying instrument like a security, ETF or even index at a predetermined price over a certain period of time. Buying and selling options is done on the options market, which trades contracts based on securities. Buying an option that allows you to buy shares at a later time is called a "call option," whereas buying an option that allows you to sell shares at a later time is called a "put option."