The Univ iPhone sold by BestBuy is not an unlocked phone but a flexi plan phone for use in the US. The phone locks to the network used to activate the phone but only works with US networks - in other words the phone DOES NOT work outside of the US and despite paying full price for the phone you are then locked to the network used to activate the phone. I would strongly recommend you instead go to the Apple Store and buy an unlocked phone from them which is completely unlocked and will work outside
of the US. It also costs the same as the BestBuy Univ iPhone. Unfortunately I learnt this from experience and once I uncovered the issue received no support from BestBuy despite specifically requesting an unlocked iPhone that would work outside the US.