Why is sand so cheap?

Could you please explain to me why sand appears to be so inexpensive? It's such a ubiquitous material that's seemingly everywhere, yet its price seems quite low. Is it because it's abundantly available, or is there another factor that contributes to its low cost? Is sand harvested in large quantities with minimal effort, or does it require significant resources to extract? Additionally, how does the market demand for sand affect its pricing? Is it simply a case of supply exceeding demand, or are there other forces at play? I'm quite curious about the economics behind this seemingly mundane material.