I don't pay for cloud storage (outside of iCloud). This is what I've got for free:
-Box = 50GB
-Copy = 20GB
-Drive = 15GB
-Skydrive = 7GB
-DropBox = 6GB
Right now, I only use DropBox, but since my 6 GB is almost used up I'm thinking about switching to something different. Or perhaps splitting up what I save on each service. For instance, Copy could be used for photos because I have more storage, whereas DropBox can be used for documents.
Get your referral link out and you can get so much more free space on Copy