This is the 255th most frequent Spanish word.
precio
Price.
In this sentence, 'precio' is used to refer to the monetary value or cost associated with the book.
El precio de este libro es muy alto.
The price of this book is very high.
In this example, 'precio' is part of an expression to denote something is of such great value that it cannot be quantified with a price.
Cuando algo no tiene precio, significa que es invaluable.
When something is priceless, it means that it is invaluable.
Here, 'precio' is used metaphorically to express the high emotional, physical, or situational cost of receiving help.