How do I stop Apple updates nagging me Apple updates keeps popping up notifications, and offers me 3 options for "Later".
How do I tell it "Never".

Some of these updates are for programs I have never used e.g. iMovie and Keynote.

I managed to hide Raw Camera updates with Option+Click but attempts to do this with Keynote, required me to logon, and then started download, which is now paused.

I have limited downloads, and don't want to waste on programs I will never use.
Open System Preferences -> App Store and disable "Automatically check for updates"

And other solution came to my mind; if you have programs that you never use and those are in App Store, then just delete those programs and install only if you need them.