Do you mean:
* The cost of throwing a party? This depends on the size of the party, the location, the food and drinks served, and the entertainment.
* The cost of a specific type of party animal? Maybe you're asking about the price of a pet?
* Are you asking about the cost of a person's partying habits? This is a more abstract question that doesn't have a clear answer.
Please clarify your question so I can give you a more helpful response!