The 23rd chapter of Genesis finds Abraham negotiating with the Hittites among whom he is living. Sarah just died, and Abraham needs a place to bury his wife. He asks the Hittite elders seated at the gate of Hebron to assign him a gravesite. Evidently he commands great respect there, because they offer him his choice of locations. He selects the Cave of Machpelah, which is on the property of a man named Ephron ben Tzohar, and requests the opportunity to buy it.
At this point Ephron speaks up. He was sitting among the Hittite elders all the time and carries on their elaborate expression of hospitality: Listen to me, my lord. I give you the field and the cave that is in it. Bury your dead. Does Abraham just say thank you and ask for the deed? Not a chance. He knows negative negotiations when he hears them. So he insists: If only you would hear me out, just accept the price of the land from me, and I will bury my dead there. Now Ephron piles on the con. No, my lord, hear me out. Land worth 400 silver shekels what is that between me and you? In other words, this is such a trifle! And just incidentally, here is the price.
Abraham proceeds to weigh out 400 shekels of silver to Ephron at a rate that the Torah describes as oveir lasokheir literally passing to the merchant. In other words, the going rate. No discount. Nothing off for inflation. Just the going rate.
Did he overpay? Clearly he did not survey neighborhood property values, and he did not make a counter offer. He heard a figure and he paid it. Not what Abraham usually does; in fact didnt he engage in a determined bargaining session with G-d Himself on behalf of the few righteous people in Sodom? And here he just accepts Ephrons price?
Consider what Jeremiah paid for a comparable field a few centuries later: So I bought the field from Hanamel for 17 shekalim. 17, not 400. Of course that field was already in his family so he had the first right to redeem it. Also, Jeremiah and his generation were coping with defeat and what we would call recession. Still, quite a difference.
However, regardless of the price Abraham paid, he established ownership of the Cave of Machpelah long before the country ever became Eretz Yisrael. This piece of land he would always own not a mere grazing ground for his livestock, but property to include in his childrens inheritance. He bought it fair and square, for the going rate.
The cave is still there, in Hebron. As far as we know, all our patriarchs and matriarchs are buried there, except for Rachel. Rachels tomb, near Bethlehem, became a target for Israels enemies in our time, as did Josephs tomb. And Hebron itself witnesses conflict now. Visiting the Tombs of the Patriarchs is a risky experience these days. Those who would drive all Jews from the Jewish state make it their policy to attack our most ancient sacred places, from Hebron to the Temple Mount.
Very likely, Abraham could not buy the Cave of Machpelah for 400 NIS (new Israeli shekels) today. But he set a precedent. No squatters rights. None of this The Ottoman rulers put us here or The British protectorate put us here so its our land! No way. You want to establish ownership? Just pay the going rate.