For example, if you bought a long call option (remember, a call option is a contract that gives you the right to buy shares later on) for 100 shares of Microsoft stock at $110 per share for December 1, you would have the right to buy 100 shares of that stock at $110 per share regardless of if the stock price changed or not by December 1. For this long call option, you would be expecting the price of Microsoft to increase, thereby letting you reap the profits when you are able to buy it at a cheaper cost than its market value. However, if you decide not to exercise that right to buy the shares, you would only be losing the premium you paid for the option since you aren't obligated to buy any shares. 
The less time there is until expiry, the less value an option will have. This is because the chances of a price move in the underlying stock diminish as we draw closer to expiry. This is why an option is a wasting asset. If you buy a one-month option that is out of the money, and the stock doesn’t move, the option becomes less valuable with each passing day. Since time is a component to the price of an option, a one-month option is going to be less valuable than a three-month option. This is because with more time available, the probability of a price move in your favor increases, and vice versa.

When buying a call option, the strike price of an option for a stock, for example, will be determined based on the current price of that stock. For example, if a share of a given stock (like Amazon (AMZN) ) is $1,748, any strike price (price of the call option) that is above that share price is considered to be "out of the money." Conversely, if the strike price is under the current share price of the stock, it's considered "in the money." 
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.
For strangles (long in this example), an investor will buy an "out of the money" call and an "out of the money" put simultaneously for the same expiry date for the same underlying asset. Investors who use this strategy are assuming the underlying asset (like a stock) will have a dramatic price movement but don't know in which direction. What makes a long strangle a somewhat safe trade is that the investor only needs the stock to move greater than the total premium paid, but it doesn't matter in which direction. 
Time Value: All options contracts have an expiration date, after which they become worthless. The more time that an option has before its expiration date, the more time there is available for the option to come into profit, so its premium will have additional time value. The less time that an option has until its expiration date, the less time there is available for the option to come into profit, so its premium will have either lower additional time value or no additional time value.

For example: Tomatoes are cheap in July and will be expensive in January, you can’t buy them in July and take delivery in January, since they will spoil before you can take advantage of January’s high prices. The July price will reflect tomato supply and demand in July. The forward price for January will reflect the market’s expectations of supply and demand in January. July tomatoes are effectively a different commodity from January tomatoes.
An equity option allows investors to fix the price for a specific period of time at which an investor can purchase or sell 100 shares of an equity for a premium (price), which is only a percentage of what one would pay to own the equity outright. This allows option investors to leverage their investment power while increasing their potential reward from an equity’s price movements.

In case of futures, a buyer of a contract is said to be “long position holder” and a seller is “Short position holder”. In the case of futures, to avoid the risk of defaulting contract involves both parties lodging a certain percentage margin of value of contract with a mutually trusted third party. Generally, in gold futures trading, margin varies between 2%-20% depending on the volatility of gold in spot market.

There is a concert of Coldplay happening in an auditorium in Mumbai next week. Mr X is a very big fan of Coldplay and he went to ticket counter but unfortunately, all the tickets have been sold out. He was very disappointed. Only seven days left for the concert but he is trying all possible ways including black market where prices were more than the actual cost of a ticket. Luckily his friend is the son of an influential politician of the city and his friend has given a letter from that politician to organizers recommending one ticket to Mr.X at actual price. He is happy now. So still 6 days are left for the concert. However, in the black market, tickets are available at a higher price than the actual price.
Options on futures began trading in 1983. Today, puts and calls on agricultural, metal, and financial (foreign currency, interest-rate and stock index) futures are traded by open outcry in designated pits. These options pits are usually located near those where the underlying futures trade. Many of the features that apply to stock options apply to futures options.
Just as you can buy a stock because you think the price will go up or short a stock when you think its price is going to drop, an option allows you to bet on which direction you think the price of a stock will go. But instead of buying or shorting the asset outright, when you buy an option you’re buying a contract that allows — but doesn’t obligate — you to do a number of things, including:
Remember, a stock option contract is the option to buy 100 shares; that’s why you must multiply the contract by 100 to get the total price. The strike price of INR 300 means that the stock price must rise above INR 300 before the call option is worth anything; furthermore, because the contract is INR 10 per share, the break-even price would be INR 310(INR 300 + INR 10).
All investors should know how to trade options and have a portion of their portfolio set aside for option trades. Not only do options provide great opportunities for leveraged plays; they can also help you earn larger profits with a smaller amount of cash outlay. What’s more, option strategies can help you hedge your portfolio and limit potential downside risk.
When buying or selling options, the investor or trader has the right to exercise that option at any point up until the expiration date - so simply buying or selling an option doesn't mean you actually have to exercise it at the buy/sell point. Because of this system, options are considered derivative securities - which means their price is derived from something else (in this case, from the value of assets like the market, securities or other underlying instruments). For this reason, options are often considered less risky than stocks (if used correctly).