The deal is that for £5 a month I can list three mobile numbers that are also on Vodafone and all 4 of us can then ring each other any time day or night for free as long as the call does not last longer than a hour, so on ours there is me my partner and my son which leaves one number free if we want to add anyone.
For £7 a month you can have up to 6 people on the list, oh and by the way only one person pays the fee it is not per person
Try this link to have a look at the phone
http://www.mobilegazette.com/lobster-575-06x07x06.htm