If you both have smartphones and both download whatsapp then texts will be free. However that relies on either wifi or a 3G signal.

You can use Skype / Voip on your mobile. I don't know the costs to call a mobile using Skype, but VoipCheapUK were 4p/min last time I checked.

buy a call card mate... my husband is from Nigeria and buys them to ring his family. you dial a London number then put the pin number in and the dial the number with the area code you want to ring.. there a different types of calling cards depending on the county you want to call.. all have different minutes and it just comes out of your credit or monthly minutes if on contract.

http://www.onlineprepaidcallingcard.com/

pay online using you debit or c card and then you are given the pin number.. or some shops you can buy them from there, like the small foreign Conner type shops .

not a lot cheaper but looks like texts are 10p and calls 11p on payg 02, free international sim, sorry i cannot post links.

Thanks for all the replies so far.

We have been using Whats app while she is in Singapore and a video calling app called Tango.

Will look into your suggestion Mrs Aniekwe.