An option's price, its premium, tracks the price of its underlying futures contract which, in turn, tracks the price of the underlying cash. Therefore, the March T-bond option premium tracks the March T-bond futures price. The December S&P 500 index option follows the December S&P 500 index futures. The May soybean option tracks the May soybean futures contract. Because option prices track futures prices, speculators can use them to take advantage of price changes in the underlying commodity, and hedgers can protect their cash positions with them. Speculators can take outright positions in options. Options can also be used in hedging strategies with futures and cash positions.
However, for put options (right to sell), the opposite is true - with strike prices below the current share price being considered "out of the money" and vice versa. And, what's more important - any "out of the money" options (whether call or put options) are worthless at expiration (so you really want to have an "in the money" option when trading on the stock market). 
Now, think of a put option as an insurance policy. If you own your home, you are likely familiar with purchasing homeowner’s insurance. A homeowner buys a homeowner’s policy to protect their home from damage. They pay an amount called the premium, for some amount of time, let’s say a year. The policy has a face value and gives the insurance holder protection in the event the home is damaged.
Spreads use two or more options positions of the same class. They combine having a market opinion (speculation) with limiting losses (hedging). Spreads often limit potential upside as well. Yet these strategies can still be desirable since they usually cost less when compared to a single options leg. Vertical spreads involve selling one option to buy another. Generally, the second option is the same type and same expiration, but a different strike.
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.

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).