First, you aren't going to find CDMA overseas- well, at least in MOST places. But because of how Apple has manufactured the iPhone 5, you can put a local carrier's SIM into your US purchased iPhone 5 and use it overseas. However, unless the phone you have operates on the same frequency as the local (overseas) LTE band, your phone will only do data at the non-LTE speed. So you will be able to spend a lot less than the AT&T (for example) overseas rates by using a local carrier- but you are likely going to be operating your phone at a somewhat slower data transfer speed than LTE- again, unless you happen to be in a market where the local LTE frequency is the same as the ones contained in your phone.
And yes, the local carriers overseas will typically have a mix of voice and data plans available on a pay as you go basis. As i said, that will usually cost you substantially less than what you would pay to use your US carrier with some sort of international package.
No, the iPhone 5 is NOT a "World" phone like the 4s was, for example. What I mean by that is that it will not operate at its peak LTE speed in ALL overseas markets because there are MANY LTE frequencies used overseas. That's why there are (at least) 3 versions of the iPhone 5 made so far- and they operate on different LTE frequencies. But it WILL work at the slower, non-LTE speeds with a local carrier SIM. But remember- there is no Universal "overseas" for purposes of LTE
Think of buying a pay as you go type package like purchasing a gift card. Once you've run through your pre-paid allotment of voice/data on whichever carrier you've purchased it from, it will stop working. But you can always add more cash to your card.
I hope that helps a bit.
Yes that helps a lot!
So, basically the world uses GSM not CDMA.
I guess my main concern is if I don't buy data or if my data runs out, would we pages just not load?
I know with att they will charge me mega overages.