Not sure how much money you will save in practice, but saving you some cash seems to be the main thrust of O2 Refresh.Here's the deal. You choose a monthly rate for the data side of things - minutes, texts and data. You then add a further cost for the actual phone hardware. Why is that a good thing? Well, if you want to change hardware, you pay off the balance of the old phone and not the data, which you can move from phone to phone.The money saving also extends to anyone who runs a contract through its full length. Once you've done your two years, the phone cost is removed, leaving you with just the data. If only every phone network could follow that lead.It kicks off from tomorrow (16 April), but despite that, O2 has yet to give concrete details of all the actual pricing across the range. But for an example, the HTC One will be £17 per month for unlimited minutes, texts and 1GB of data, with a further £20 per month charged for the phone itself, plus a £49.99 up front fee.When it does launch, the offer should extend to the iPhone 5, Samsung Galaxy S III, HTC One, BlackBerry Z10, Samsung Galaxy Note 2 and Sony Xperia Z, with the Samsung Galaxy S4 added in future.