How much did Abraham pay Ephron the Hittite for the cave for his wife’s tomb, even though it was offered as a gift?

Abraham bought the cave of Machpelah for 400 shekels of silver. Initially, Ephron appeared to offer it as a gift to Abraham. However, according to Middle Eastern custom, that was just a polite way of opening the negotiations – both parties understood that the offer was not to be taken at face value! So later in the conversation, when Ephron casually mentioned the value of the land, Abraham paid that amount to buy the cave.