I assume there's a catch to that "freebie"?
The short version: No. She would pay the same as she paid before but she gets a new phone every 2 years and double the mobile data allowance she did before.
Longer version: Not really, as far as my wife is concerned. She's in a contract that originally entitled her to a phone (which she received), then I bought her an N5 when the old phone proved a miserable failure, then two years went by on that contract (which entitles her to a new phone).
My mind boggles at paying £30/month for mobile access, but then I like a high end smartphone even though my needs are minimal, so it makes more sense for me to buy a phone myself and then couple it with a minimal tariff (I pay half of what my wife pays per month). My wife on the other hand has been using all her mobile data allowance and then a little more and paying the extra for it, whereas this tariff gives her double the mobile data allowance she previously had at the same cost as she's been paying in total.
Before anyone asks, there's no point in us shopping around for another provider in the hopes of a better deal since we live in a part of the UK where all the other providers have significantly worse reception than the one we're with.