Strike Price: This is the price at which you could buy or sell the underlying futures contract. The strike price is the insurance price. Think of it this way: The difference between a current market price and the strike price is similar to the deductible in other forms of insurance. As an example, a December $3.50 corn call allows you to buy a December futures contract at $3.50 anytime before the option expires. Most traders do not convert options to futures positions; they close the option position before expiration.
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.
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. 
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’s another potential problem if you base your decision solely on commissions. Discount brokers can charge rock-bottom prices because they provide only bare-bones platforms or tack on extra fees for data and tools. On the other hand, at some of the larger, more established brokers you’ll pay higher commissions, but in exchange you get free access to all the information you need to perform due diligence.

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.
An option is a contract that allows (but doesn't require) an investor to buy or sell an underlying instrument like a security, ETF or even index at a predetermined price over a certain period of time. Buying and selling options is done on the options market, which trades contracts based on securities. Buying an option that allows you to buy shares at a later time is called a "call option," whereas buying an option that allows you to sell shares at a later time is called a "put option."