Pay a “premium” wherever you buy a commodity option. Let's say you purchase a “call” option on 100 bushels of corn, and the premium is $2 per bushel. You will pay $200 for the right to exercise your option until it expires. That is your only cost to purchase the option, except for whatever commission you had to pay to your brokerage company. Even if you choose not to exercise the option before it expires, your investment will be limited to the $200 premium plus commission.
However, options are not the same thing as stocks because they do not represent ownership in a company. And, although futures use contracts just like options do, options are considered lower risk due to the fact that you can withdraw (or walk away from) an options contract at any point. The price of the option (its premium) is thus a percentage of the underlying asset or security.