When buying an iPhone outright the best place to do this is at the Apple Store, not one of the side kick stores selling Apple. I purchased mine outright from Apple as I loathe contracts.
Before I went to the Apple store to purchase my beloved iPhone I did go into one of the side kick stores where they offered a better price for the phone but there was the catch that you had to sign up on a contract with Vodafone and that simply was not an option.
I am with Telstra at the moment on a $130/mth member plan, gives me $2000 included calls 150mb browsing, and as the actual call rates are so low on this plan I dont get any where near the $2000 worth of included calls.
As for NextG I am still amazed at the coverage I get in the places I go.