Unlike other investments where the risks may have no boundaries, options trading offers a defined risk to buyers. An option buyer absolutely cannot lose more than the price of the option, the premium. Because the right to buy or sell the underlying security at a specific price expires on a given date, the option will expire worthless if the conditions for profitable exercise or sale of the option contract are not met by the expiration date. An uncovered option seller (sometimes referred to as the uncovered writer of an option), on the other hand, may face unlimited risk.
A long options trade is entered by buying an options contract and paying the premium to the options seller. If the market then moves in the desired direction, the options contract will come into profit (in the money). There are two different ways that an in the money option can be turned into realized profit. The first is to sell the contract (as with futures contracts) and keep the difference between the buying and selling prices as the profit. Selling an options contract to exit a long trade is safe because the sale is of an already owned contract.
With respect to an option, this cost is known as the premium. It is the price of the option contract. In our home example, the deposit might be $20,000 that the buyer pays the developer. Let’s say two years have passed, and now the developments are built and zoning has been approved. The home buyer exercises the option and buys the home for $400,000 because that is the contract purchased.

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. 
For instance, it is possible to construct an option strategy in the futures markets that is affordable without sacrificing the odds of success...but with the convenience comes theoretically unlimited risk. This is easier than it sounds, similar to the way you would borrow money to pay for a house or a car, you can borrow money from the exchange to pay for long commodity option trades. There are an unlimited number of combinations of self-financed trades but they are typically going to involve more short options than long options, or at least as much premium collected on the sold options than that paid for the longs. In essence, the money brought in through the sale of the short options goes to pay for the futures options that are purchased. The result is a relatively close-to-the-money option with little out of pocket expense but theoretically unlimited risk beyond the strike price of the naked short options.
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.

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.
There are also exotic options, which are exotic because there might be a variation on the payoff profiles from the plain vanilla options. Or they can become totally different products all together with "optionality" embedded in them. For example, binary options have a simple payoff structure that is determined if the payoff event happens regardless of the degree. Other types of exotic options include knock-out, knock-in, barrier options, lookback options, Asian options, and Bermudan options. Again, exotic options are typically for professional derivatives traders.
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).