CoffeewithGames shows the sales ranks for God of War between April 25 and May 31, in chart form.
CwG says in one section, "The lowest sales rank I recorded, for God of War III during May, was #22 on May 31 around 11:50PM. It was also ranked #22 on April 28 around 12:45AM."
CwG then talks about the "Critical Reception & Price Drops" for God of War III, saying, "The thing that is surprising to me, is how quickly the price has dropped on God of War.
It has not even been out a full 3 months, and it has been having significant price-cuts."