I found for my family that Microsoft's Office 365 was a good deal. We get office across the families devices and each member gets 1TB of storage for onedrive. All for 99 bucks a year. The only complaint I have about the arrangement is that the one drive app doesn't really upload photos in the background cleanly. It needs access to gps to hack its way as a background service. A practice that is common amongst competitive cloud storage providers. However it works.
nice thing about one drive is the photos are files and don't get sucked up into Photo's database. Not as elegant as using apple's native cloud storage, but until family sharing of iCloud storage happens its the most cost effective way.