And how about so called calling cards in UK? Here in US to call UK or almost any other country it costs around 1-1.5 cents a minute. 

http://www.comfi.com/phone-cards/UK-London

My cell phone is automatically recognized by calling company (by the way as to cell phone alone for any use, I pay T-mobile $39.99 for 1500 minutes /month) Why bother with anything else? Even free Skype is only interesting after that if you do videochat or do talking 24/7/365