You pay a premium to the seller to acquire this right.
Buying a put option gives you the right, but not the legal obligation, to sell an underlying asset at a predetermined "strike price" until a specific "expiration date". This is fundamentally a position; you profit when the underlying asset's price falls. Core Mechanics of a Long Put When you purchase a put, you are "long" the option. what happens when you buy a put option
Put options: What they are, how they work and how to buy and sell them You pay a premium to the seller to acquire this right
What happens at expiration depends on the stock price relative to your strike price: but not the legal obligation