What is a cost in networking?

Excuse me, could you elaborate on what exactly constitutes a "cost" in the context of networking? Is it referring to the monetary expenses incurred for setting up and maintaining a network infrastructure? Or does it encompass non-financial costs such as the time and effort invested in establishing and maintaining connections with other networks or individuals? Additionally, are there any specific costs that are more prevalent or significant in the realm of cryptocurrency networks, considering their unique nature and requirements? I'm eager to gain a deeper understanding of this concept.