For anyone having issues getting the upgrade, or if you’ve never owned the iWork suite, so don’t have the apps to update, you can just download the iWork ’09 trial version
The App Store will then allow you to upgrade to the new versions, for free.
1) Visit http://mac.softpedia.com/get/Business/Apple-iWork-06.shtml
2) Click Download
3) Click External Mirror 1
4) It will just be a DMG file so install like normal
5) I had to wait a few minutes / I also Quit App Store and reopened. After a few minutes it showed I had 3 updates available to Pages, Numbers, Keynote.
6) Updated as normal.
A common issue is an error message “cannot be installed because it’s from an unidentified developer”. To fix this:
System Preferences -> Security -> General -> Allow apps downloaded from “Everywhere”