iCloud Full

[Dr Winston O Boogie jr]

I'm getting a message that my iCloud is full and they want me to purchase more storage space.
The question I have is can I delete some stuff from iCloud to open up more space.
I don't really know what stored there and I would like to take a look to see if there are files and/or programs that I no longer need or use.

I wasn't aware that iCloud had limited free storage and that I was going to need to buy more down the road. How is this going to work? Am I going to have to keep buying more and more iCloud storage every year or ever few months?

[Dr Winston O Boogie jr]

I just went into System Preferences in my desktop and looked at iCloud. It shows two iPhones. One that was backed up on Feb 23 and one that has never been backed up. I bought a new iPhone 6+ recently and am wondering if the one that was backed up was the old one. If that's the case, should I delete the old one and back up the new one?

Also it shows that I have 2.29 GB of backup available, but when I turn on my phone or iPad it says that iCloud is full.

Anyone have any idea what's going on here?