Can I install the "app store" in an IOS simulator?
This is NOT possible
The Simulator does not run ARM code, ONLY x86 code. Unless you have the raw source code from Apple, you won't see the App Store on the Simulator.
The app you write you will be able to test in the Simulator by running it directly from Xcode even if you don't have a developer account. To test your app on an actual device, you will need to be apart of the Apple Developer program.
You can install other builds but not Appstore build.
From Xcode 8.2,drag and drop the build to simulator for the installation.