I know Capras told me they will beat any price as long as they don't loose money on it. You'll find inventory constantly changing at all of the guns shops, especially used inventory.
As for 9mm vs 40 that's an endless debate. 40 ammo is easier to find right now if you want to factor that in. Used for self defense though neither is far superior to the other. You get more rounds in the mag with the 9mm then with the 40. It really all comes down to which factors are important to you.