I know my verizon phone didn't even come with it. I managed to find a .apk online and was able to use it.. you can also get to it indirectly several ways... If you go into camera and download more effects it takes you into the store. If you are using touch wiz, within the app drawer you can click on "galaxy essentials," from the drawer settings drop down menu.
I just dont really know why you would use their app store though.