'Shekels' in the Bible

And when he had his hair cut, (which he did at the end of every year, because of the weight of his hair;) the weight of the hair was two hundred shekels by the king's weight.

And there came against David one of the offspring of the Rephaim, whose spear was three hundred shekels of brass in weight, and having a new sword, he made an attempt to put David to death.

And the king said to Araunah, No, but I will give you a price for it; I will not give to the Lord my God burned offerings for which I have given nothing. So David got the grain-floor and the oxen for fifty shekels of silver.