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.

On the other hand, commodity option buyers are exposed to limited risk and unlimited profit potential, but they also face dismal odds of success on each individual speculation. For this reason, we often refer to the practice of buying options in the commodity markets as the purchase of a lottery ticket. It probably won’t pay off but if it does the potential gain is considerable. Conversely to the commodity option seller, an option buyer views the position as an asset (not a liability) until it is sold or expires. This is because any long option held in a commodity trading account has the potential to provide a return to the trader, even if that potential is small.
In terms of valuing option contracts, it is essentially all about determining the probabilities of future price events. The more likely something is to occur, the more expensive an option would be that profits from that event. For instance, a call value goes up as the stock (underlying) goes up. This is the key to understanding the relative value of options.

$4.95 commission applies to online U.S. equity trades in a Fidelity retail account only for Fidelity Brokerage Services LLC retail clients. Sell orders are subject to an activity assessment fee (from $0.01 to $0.03 per $1,000 of principal). Other conditions may apply. See for details. Employee equity compensation transactions and accounts managed by advisors or intermediaries through Fidelity Clearing & Custody Solutions® are subject to different commission schedules.
The fee you are paying to buy the call option is called the premium (it's essentially the cost of buying the contract which will allow you to eventually buy the stock or security). In this sense, the premium of the call option is sort of like a down-payment like you would place on a house or car. When purchasing a call option, you agree with the seller on a strike price and are given the option to buy the security at a predetermined price (which doesn't change until the contract expires).