I just ordered my iphone 4s, at the "upgrade" price because I was patient enough not to jump at the iphone 4, when I first became eligible. I wanted to share this with any of you who may be thinking about buying one, because some requirements have changed.
This info applies to AT&T customers, and I am not sure if any of these changes have occurred with other carriers, as well. If you are new to AT&T, or this is the first time you are buying a smart phone, then this info doesn't really apply to you, either. However, if you already have an iphone (or other smart device) and are attempting to buy the 4s online, you will see a message saying your data plan is no longer sufficient and AT&T is trying to replace it with a comparable one. My old iphone plan had an unlimited data plan, which is no longer an option. If you also currently have an unlimited data plan, DON'T BUY YOUR 4S ONLINE. CALL AT&T to purchase it!
The existing customers who already have an unlimited data plan are going to be "grandfathered" in to their new plans, and are able to keep their data unlimited, for the current price they're paying. If you buy your phone online, your unlimited plan will be removed when you choose the new option, and you will NOT be able to get it back. If you call AT&T and order through a representative, they will make a note of this in your file, as well as send you a confirmation email, that you are still going to receive UNLIMITED data with your plan (make sure you ask your customer service rep. to specifically mention the data plan in your post-call email).
You will have to call AT&T to activate your phone when you receive it, and mention the unlimited data plan you are eligible for, as a previous customer. As I said, there will be a note in your file, and also an email to help you prove you deserve to be on the unlimited data, once again.
IF YOU DON'T DO THIS WHEN YOU BUY YOUR IPHONE 4S, YOU WILL END UP WITH A NEW, LIMITED DATA PLAN. IT WILL BE EXPENSIVE, AND IF YOU GO OVER YOUR LIMIT THEY WILL CHARGE YOU FOR ANY ADDITIONAL DATA USED.