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.
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). 
The potential home buyer would benefit from the option of buying or not. Imagine they can buy a call option from the developer to buy the home at say $400,000 at any point in the next three years. Well, they can—you know it as a non-refundable deposit. Naturally, the developer wouldn’t grant such an option for free. The potential home buyer needs to contribute a down-payment to lock in that right.
Call writers and put writers (sellers), however, are obligated to buy or sell if the option expires in-the-money (more on that below). This means that a seller may be required to make good on a promise to buy or sell. It also implies that option sellers have exposure to more, and in some cases, unlimited, risks. This means writers can lose much more than the price of the options premium.

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. 

As an example, let's say a farmer is expecting to produce 1,000,000 bushels of soybeans in the next 12 months. Typically, soybean futures contracts include the quantity of 5,000 bushels. The farmer's break-even point on a bushel of soybeans is $10 per bushel meaning $10 is the minimum price needed to cover the costs of producing the soybeans. The farmer sees that a one-year futures contract for soybeans is currently priced at $15 per bushel.
With this strategy, the trader's risk can either be conservative or risky depending on their preference (which is a definite plus). For iron condors, the position of the trade is non-directional, which means the asset (like a stock) can either go up or down - so, there is profit potential for a fairly wide range. To use this kind of strategy, sell a put and buy another put at a lower strike price (essentially, a put spread), and combine it by buying a call and selling a call at a higher strike price (a call spread). These calls and puts are short.  
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.