Lebara today announced that it was offering 0 cent a minute rates for prepaid calls to mobiles or landlines to China, India, Malaysia and Thailand, as well as landline calls to Indonesia. For all those countries, you merely pay a 25 cent flagfall.
If you regularly wanted to call family in those countries and haven't set up a totally free option such as Skype-to-Skype calls, this is a pretty cheap deal. However, there's a fair use policy attached, which says that excessive use (more than 5000 minutes a month) can result in termination of the service. You can also be cut off for actions which "adversely affect the Vodafone Network or other Vodafone customers’ use of or access to a Vodafone Service" (Lebara uses Vodafone as its wholesale supplier).
In practice, that means that Lebara has plenty of grounds for cutting you off if it deems your usage to be excessive. 5000 minutes a month equates to under 3 hours a day — way longer than I'd want to talk on the phone, but not utterly exceptional for some of my relatives. If you're making brief but regular calls, it's potentially a better and less risky deal. That said, if the calls are really brief, then a lower flagfall plan might suit you better and cost less.