iPhone 3G Contract Question

[applew]

I currently have an iPhone and so does my wife. We have a family plan(700 min) with two data plans+ 200 text messages. We pay 69.99+20(my data plan)+20(her data plan) = 109.99 comes out to about 130 a month after tax and the extra charges.

I would like to purchase one 3G iPhone, and keep my wife's old iphone with her 2G data plan. So the math would look like: 69.99 + 30(My new 3G data plan) + 20(her current 3G Data plan) + 5 (for my 200 text messages) = $124.99

The problem is that I see that the only plan that is available is 129.99 for two 3G iPhones. So my question is... am I or has anyone been able to just buy one 3G iPhone and keep the old 2G data plan on another phone?

Or else I would end up paying for her 3G plan even though she has an old 2G iPhone

The math:
69.99 + 30(My 3G Plan) + 30 (her 3G plan even though she has a 2G phone) + 5 (my 200 text messages) + 5(her 200 text messages) = $139.99

$139.99 - $124.99 = $15 dollar difference a month
= me not getting the iPhone

function mood(){

if($iphone_plan_does_work_out){

$happy = true;

} else {

$happy = false

}

return $happy;

}


mood();





sorry for the poor, grammer; and spellng