Shocker: AT&T does something nice for iPhone users
itworld.com
itworld.com
(MMS and SMS used to be on separate pricing tiers but a couple years back all the US carriers switched this and count them as the same. You can't buy a MMS plan from AT&T Wireless anymore, though some legacy customers may have something similar. Humorously, AT&T had to create a SMS only plan for the iPhone since it was the only device they carried without MMS support.)
Source? The only data I could find was WAY old (2006) but had the global price of MMS pegged at 4x the price of SMS [1].
You can claim that some plans come with MMS/SMS allotments, therefore they are the same price. That still isn't the same cost, because providers will dock you for a message + the data. That means you need an unlimited data plan AND a text plan for them to essentially be the same price.
It then follows that it makes perfect sense that AT&T would do this. All iPhone users MUST have an unlimited data plan, easily covering the data of sending MMS.
[1] MMS pricing worldwide http://telephonyonline.com/wireless/metrics/mms_pricing_worl...
They have treated SMS/MMS as the same for quite some time. I forget who switched first (I want to say Alltel which is now part of Verizon), but it was a very short time between the first and the last.