Q: HI I can't download iOS 8 version which I think is stopping me from downloading games and other apps?  I Rethought maybe I didn't have enough space on the iPad so bought the package that gives 20GB per month for $1.29 a month? i Really don't know wha

That 20GB is not on your iPad it's on Apple's iCloud server. it won't help install iOS 8.

What size iPad do you have? How much of the storage is available?

Purchasing additional storage for your iCloud account does not make more space available on your iPad. If you need more space for an iOS update, read this article: If you need more space for an iOS update - Apple Support

iCloud storage has nothing to do with space/storage on the iPad. That storage is fixed, and you cannot change it. When you are trying to download iOS 8, what kind of error message do you see that makes you think that storage is the problem? Are you trying to update OTA on the iPad? Connect the device to the computer and iTunes and update that way.