There is Unity Free, and Unity Pro…
Then there are Other options below…
With Unity Pro, does that give me the option to develop on the iOS? or Do I need to purchase the iOS/iOS Pro along with the Pro version of Unity?
I am asking because I only want to develop on the iOS, so I do not need the original Unity Pro, only Unity free + iOS Pro right? but I cannot choose that option.
Maybe I over confused myself lol…but I mainly want to just develop on the iOS.
Unity Pro = The base for all Pro options. Gives you all the features required to use it on iOS and Android. ONLY Publishes to PC, Mac, and Linux.
Unity Free + iOS Basic = The minimum needed to publish on iOS.
Unity Pro + iOS Pro = Unity Pro features on iOS, in basis.
Unity Free + iOS Pro would be worthless. You can’t use any features of iOS Pro without having Unity Pro, thus, having to purchase Unity Pro.
You can buy Unity Free + iOS Basic, or Unity Pro + iOS Pro.
Unity Pro + iOS basic is possible as well, but I guess you simply cannot use the Pro features for your iOS build then but only in PC/Mac/Webplayer builts.
And actually the store doesn’t even allow you to purchase iOS Pro if you haven’t got Unity Pro itself.
So as pivotraze mentioned: For the basic setup you’ll need at least Unity Free + iOS Basic.
For Pro features you’ll definitely need Unity Pro + iOS Pro.
Ah ok, well thank you both I think I may try the free/iOS and see how I do at first i can always expand later I suppose. Are either of you using both versions of pro or either?
Thx fir the quick responses 
Just upgraded to Unity 4 Free + iOS Basic + Android Basic lately. Sooner or later I’m upgrading to Pro as well as I will need some of the Pro features (Light Probes, dynamic shadowing, possibly Occlusion Culling, IK rigs in Mecanim and such) as they will add quality to the project, but that’s nothing I need to do now. Instead I’ll have an eye on possible future discounts first… 
Afaik you only pay the difference, so it’s ok to test the waters if you want.