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.
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.
When purchasing put options, you are expecting the price of the underlying security to go down over time (so, you're bearish on the stock). For example, if you are purchasing a put option on the S&P 500 index with a current value of $2,100 per share, you are being bearish about the stock market and are assuming the S&P 500 will decline in value over a given period of time (maybe to sit at $1,700). In this case, because you purchased the put option when the index was at $2,100 per share (assuming the strike price was at or in the money), you would be able to sell the option at that same price (not the new, lower price). This would equal a nice "cha-ching" for you as an investor.
However, options are not the same thing as stocks because they do not represent ownership in a company. And, although futures use contracts just like options do, options are considered lower risk due to the fact that you can withdraw (or walk away from) an options contract at any point. The price of the option (its premium) is thus a percentage of the underlying asset or security.