Sonar Tel www.sonartel.com

It may be slightly cheaper than the competition but quality is horrible. Busy signals are becoming the norm. Their systems somehow mix up the number you dialed and end up dialing another number in another country. I got charged multiple times and customer service does not resolve issues in a timely manner.

The Sonar tel prepaid is absolutely superb. It is the most reliable prepaid service I have ever used. I highly recommend this service to anyone. I am able to make calls to a lot of destinations that some calling cards cannot get to.