I have some old macs which cannot update to OSX 10.12, however this is the minimum requirement for installing those applications from the app store. Please could someone advise how to get an older, compatible version of this software legally through Apple? Thanks!
I had this issue too. Whenever I used an Apple ID that hadn't previously downloaded iWork I wasn't able to download the free version on 10.11. I even tried this workaround.
What did work was getting access to a 10.12 Mac. Downloading Pages, Numbers and Keynote. The apps were now associated to that Apple ID. I then went back to the 10.11 Mac's, signed in using the same ID and clicked download. The App Store displayed a message asking if I would like to download an older compatible version.