This service also acts as a calling card, as you will be texted a PIN for use from any other phone line.
International call charges start at 0.5p/min with a connection charge equal to 2 minutes' call time capped at 30p. Access to the service is available via a London number or an 03 number, both of which are charged as standard landline numbers and qualify for inclusive minutes on a landline or mobile, or via a 0800 freephone number - use of this will incur an additional 2p/min charge off your balance - or 20p/min if used from a payphone.
Top-ups are available for £3 or £5, plus one standard text message charge per top-up.
Top-up service is available in the UK only, use while roaming is not recommended (though in EU calls to non-EU locations are likely to work out cheaper than a direct dialled call).
This is not an internet calling service, indeed this app does not have internet permissions. It's a gateway for using your phone as a phone to call abroad more cheaply than a direct call. 3G not required, this will work just as well on a 2G signal.