What is cost on a network?

Could you please clarify what you mean by "cost on a network" in the context of cryptocurrency and finance? Are you referring to the transaction fees associated with sending or receiving digital assets on a blockchain network? Or are you asking about the operational costs incurred by maintaining and securing the network infrastructure? Additionally, could the cost also encompass the economic and energy expenses associated with mining or validating transactions on a proof-of-work blockchain? Understanding the specific context would help me provide a more accurate and comprehensive answer.