Pfingo is giving free calls using their apps ( Sorry , only for Android phone users) . Free unlimited calls to Singapore plus 20 minutes global call . You can use it anywhere oversea and call back Singapore .As long as there you have a stable internet connection. Try it next time when you travel .Save on roaming and expensive paid international call.
See my screenshoots below. Click on the links to download the apps on Google Play. Visit their website for more information