
"Because the single itself is fairly old -- it premiered in June -- there is more focus on Cyrus' new song, "Wrecking Ball." The cut premiered on iTunes late Saturday night as part of the "Bangerz" pre-order, and is off to a robust sales start. Sources suggest that it moved around 80,000 to 90,000 copies in less than two full days on sale."
BuyWrecking Ball and pre-order Bangerz!

source