you are joking right? ASP aka the average selling price of the iPhone 4 for apple is about $625
so apple get any where between $350 to $450 from ATT/Verizon/Sprint for each and every iPhone sold ...
there is a article somewhere in the macrumors
Do you really think that Verizon/Sprint/at&t pay the difference between subsidized and retail? Not likely. I would guess that the $200 figure mentioned before is pretty close. When large corporations buy millions of anything, they don't pay retail.