Why do keys cost so much?

I'm curious, why do keys in the cryptocurrency world cost so much? It seems counterintuitive that a digital asset, which doesn't have any physical form, would carry such a high price tag. Could you please explain the reasoning behind this? Are there specific factors that contribute to the cost of keys, and if so, what are they? Additionally, is there a way to manage or reduce the cost of keys, or is it something that's inherently tied to the nature of cryptocurrency? I'd love to gain a deeper understanding of this topic.