Make online calls to mobile & landline phones. PopTox lets you make free VOIP calls from your PC or Smartphone using WiFi or internet only. You can use PopTox from any standard web browser. No need to download apps or plug-ins. Absolutely no payment is required. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.