Genesis 23:14,15

‘And Ephron answered Abraham, saying to him, “My lord, hear me. A piece of land worth four hundred shekels of silver, what is that between me and you. Therefore bury your dead ”.'

Ephron seemingly offhandedly, but really in deadly earnest, names his price and it appears to be a stiff one. Omri will later buy the site of the whole city of Samaria for six thousand shekels (1 Kings 16:24). So either the field was very large or Ephron has his eyes on a big profit. He is well aware that Abraham is gaining more than a field.

“Four hundred shekels of silver.” Prices were paid by weight of silver and not by coinage which made its appearance much later.