How much does it cost to run a network?

As a crypto enthusiast and investor, I'm often curious about the operational costs of running a cryptocurrency network. Could you elaborate on the various expenses involved in maintaining a blockchain-based system? Specifically, I'm interested in understanding the costs of hardware, software, energy consumption for mining, and any other significant overheads. I'm also keen to know if there are any scalability issues that might drive up costs as the network grows in size and popularity. A detailed breakdown of these expenses would greatly assist in my understanding of the economic dynamics of running a cryptocurrency network.