go to the cave where the hill giants live.go to the very corner and take the arrows from the archers when they are on the ground.then you can keep them in your inventory and sell them in the GE or you can SOMETIMES sell them to archers in the cave for good $MONEY$!while you wait for the arrows to appear on the ground kill some hill giants for their big bones.
Probably workes best in a world with a lot of people