Ordering Iphone without pro-rated data plan

Hey guys I want to order a 3gs for upgrade but ATT keeps wanting to charge me a prorated 30 dollars for the data plan. What I want to do is order the phone using someone elses upgrade and then add the data plan to my SIM through the itunes activation. I already pay for a data plan on my phone, and ordering online with the prorated data plan would add an extra 30 dollars to the monthly bill ONTOP of the data plan i already pay for