Just found this. I don't think you can order it online.
Friends & Family Mobile – £1.50 a month. For residential customers on a BT Calling Plan. A 12.5p call set up fee applies.
Hi there needless to say that infomation is not on there.
presumably you get ?certain amount free after the set up fee,
sorry but my sister-in Law doesn't live near me and is working, so
can't ask her.
EDIT I just found this in another post: £1.50 per month which is supposed to offer you calls to UK mobiles at a reduced price of 7p per minute
Hi there.....just to answer a couple of questions regarding "The calls to mobiles from your B.T land line package"....
Firstly if you hav'nt got this one ring 0800 800 150.....they will sort it..its £1.55 a month in advance.
Secondly, I thought I had to give 3-4 chosen mobile No's to qualify for the discount when I originally chose this add on but never got around to doing that,
I've just found out that it refers to ANY U.K mobile Number. ( I think you only get given this option online when you first make your line order or when you upgrade??) Hope this helps.