hey guys i own a first gen 8gb iphone. im currently on atnt service. since i am on a family plan my portion of the bill is 35 dollars and i share minutes with my sister. but i want to know if i bought a 3g iphone used and insert my sim card will i get service? will i get 3g service? or DO I HAVE to renew my contract buy a new 3g iphone from atnt in order to get the 3g service? what im trying to avoid is renewing my contract and also avoiding the higher prices of the 3g bill. not sure if my 35 dollar portion of the bill would go up if i did renew the contract anyways?