p3p cache map go ipad air

FYI, B&H Photo web site is listing P3P with a free battery for $899. DJI advertising same package for $999.

I've searched for the answers to these - but obviously not extensively enough because I am asking... Does anyone have information about how much storage is allowed by the apps that support iPad/P3P? Is the storage of cached maps managed by the app or by the device? I am wondering because I...