If I change phones will my internet plan cost more?

I have a samsung eternity with the internet data plan, which is $10 a month with at%26amp;t. And my freind is canceling his plan, if i bought his iphone, popped it open and put my sim in it, would my data plan change to $30 a month for the internet? $30 a month is how much the iphone's internet data plan is, but how would at%26amp;t know i changed phones?If I change phones will my internet plan cost more?
AT%26amp;T can detect what phone you're using. As soon as the network detects that you're using an iPhone, the $30/month data plan will be added to your account.If I change phones will my internet plan cost more?
you will pay the 10, DONT TELL THEM U CHANGED THE PHONE and NEVER give them the IMEI ..and they will never know