We've seen a few readers complaining that after upgrading to iOS 7 the iTunes Store app on their iPhone or iPad won't launch and just crashes immediately after trying to open it. From what we've managed to dig up, you aren't alone in having the issue but fortunately, there are a few solutions that seem to be working for people.
Here they are:
If the app is still crashing, keep reading. If the iTunes Store app now works, that's it.
You should be re-routed to the iTunes Store app. This time, it should load just fine. You should only have to do this one time and find that after loading it through the Music app, the iTunes Store app loads fine on its own. If it doesn't or it's still crashing, continue on.
People that have it set to Always seem to be the ones having trouble connecting to the iTunes Store app for some reason.
If you've tried all the steps above and you still can't launch the iTunes Store app, you may have to fully restore your iPhone or iPad. If you've found another workaround or solution that worked for you, let us know in the comments!