Page 1 of Vodafone Half price Texts

Hello Everyone

Last year my cousin told me about a code you can put into your vodafone phone and she said she would get me it of her friend it turns out her frined has changed networks and no longer knows the code. Does anyone no were i can find the code please as texting my friend who has moved out of town a lot of money now.

Thanks in advance

Becky :)