Rebtel

Rebtel is a voice over IP application that lets you call other users for free. There are applications available for Windows, iOS, Android and Windows Phone.

You can call other Rebtel users for free, and you can also call landlines and cell phones around the world. There is also SMS support. When you sign up for the service, you get 5 bonus minutes that help you test the service. After those minutes have been used, you can add credit to your account using a credit card. You can check the up-to-date calling rates on the website, but you will also see the rate below the number when you are trying to place a new call, which is a great way to calculate how much a call costs during it or before you start it.

After installing the application and setting up an account, you can start making calls. I found that calling landlines and cell phones was easier than calling other Rebtel users at first. The way I tested the app was by installing the app on my iPhone and then on my PC. I then tried to call my cell phone number from the PC app directly, but no matter what I did the app would call my cell phone number and not Rebtel on my phone. So I decided to create a contact for my cell phone number. At first, this didn't work either, but after I clicked on the "Invite" button, I was able to call my cell phone for free from my computer (both had Rebtel installed and running). The quality of the call was quite good. The call was made quickly and I didn't find any lag during my test call.

The calling rates for Rebtel seem to be one of the lowest ones you can find. There is even a program in place that gives you free credit for each user that you invite who makes a payment to Rebtel.

If I was to compare this to Skype, the leading provider of VOIP services, this app seems incomplete. It doesn't have support for video chats, or instant messaging. It is not available on the Mac and the whole approach to adding contacts seems more complicated. But, if you only need an app to call cell phones or landlines around the world, this is a really good solution. It is very cheap and the quality of the calls is rather good.