Contract Months (Time): All options have an expiration date; they only are valid for a particular time. Options are wasting assets; they do not last forever. For example, a December corn call expires in late November. As assets with a limited time horizon, attention must be accorded to option positions. The longer the duration of an option, the more expensive it will be. The term portion of an option's premium is its time value.
So, call options are also much like insurance - you are paying for a contract that expires at a set time but allows you to purchase a security (like a stock) at a predetermined price (which won't go up even if the price of the stock on the market does). However, you will have to renew your option (typically on a weekly, monthly or quarterly basis). For this reason, options are always experiencing what's called time decay - meaning their value decays over time. 

The purchase of a call option is a long position, a bet that the underlying futures price will move higher. For example, if one expects corn futures to move higher, they might buy a corn call option. The purchase of a put option is a short position, a bet that the underlying futures price will move lower. For example, if one expects soybean futures to move lower, they might buy a soybean put option.
Combinations are trades constructed with both a call and a put. There is a special type of combination known as a “synthetic.” The point of a synthetic is to create an options position that behaves like an underlying asset, but without actually controlling the asset. Why not just buy the stock? Maybe some legal or regulatory reason restricts you from owning it. But you may be allowed to create a synthetic position using options.
Another example involves buying a long call option for a $2 premium (so for the 100 shares per contract, that would equal $200 for the whole contract). You buy an option for 100 shares of Oracle (ORCL) for a strike price of $40 per share which expires in two months, expecting stock to go to $50 by that time. You've spent $200 on the contract (the $2 premium times 100 shares for the contract). When the stock price hits $50 as you bet it would, your call option to buy at $40 per share will be $10 "in the money" (the contract is now worth $1,000, since you have 100 shares of the stock) - since the difference between 40 and 50 is 10. At this point, you can exercise your call option and buy the stock at $40 per share instead of the $50 it is now worth - making your $200 original contract now worth $1,000 - which is an $800 profit and a 400% return. 
$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 price at which you agree to buy the underlying security via the option is called the "strike price," and the fee you pay for buying that option contract is called the "premium." When determining the strike price, you are betting that the asset (typically a stock) will go up or down in price. The price you are paying for that bet is the premium, which is a percentage of the value of that asset.