When you’re browsing the iTunes Store or App Store on your iOS devices, you might come across app or music album that you want to download later.
You might be delaying the purchase, or not connected to Wi-Fi, or you might not have the password with you to the Apple ID account for the download. You can add these items to your Wish List.
Go to the main description page of the app or music album on iTunes Store or App Store. Tap on the Share icon at top right corner, and then tap the Add to Wish List option.
To look at what’s in your Wish List later, just tap the Wish List icon at top right corner of the top bar in iTunes Store or App Store.
You can not at the moment add individual music track to the Wish List, only albums. Maybe we will see this supported in iOS 8.