Options are available as either a Call or a Put, depending on whether they give the right to buy, or the right to sell. Call options give the holder the right to buy the underlying commodity, and Put options give the right to sell the underlying commodity. The buying or selling right only takes effect when the option is exercised, which can happen on the expiration date (European options), or at any time up until the expiration date (US 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).
Still other traders can make the mistake of thinking that cheaper is better. For options, this isn't necessarily true. The cheaper an option's premium is, the more "out of the money" the option typically is, which can be a riskier investment with less profit potential if it goes wrong. Buying "out of the money" call or put options means you want the underlying security to drastically change in value, which isn't always predictable.
With straddles (long in this example), you as a trader are expecting the asset (like a stock) to be highly volatile, but don't know the direction in which it will go (up or down). When using a straddle strategy, you as the trader are buying a call and put option at the same strike price, underlying price and expiry date. This strategy is often used when a trader is expecting the stock of a particular company to plummet or skyrocket, usually following an event like an earnings report. For example, when a company like Apple (AAPL) is getting ready to release their third quarter earnings on July 31st, an options trader could use a straddle strategy to buy a call option to expire on that date at the current Apple stock price, and also buy a put option to expire on the same day for the same price.
The price at which you agree to buy the underlying security via the option is called the "strike price," and the fee you pay for buying that option contract is called the "premium." When determining the strike price, you are betting that the asset (typically a stock) will go up or down in price. The price you are paying for that bet is the premium, which is a percentage of the value of that asset.