Telvio

Telvio is a mobile app for cheap international calls. It routes calls over WiFi or mobile data to any landline or mobile number in more than 200 countries, so you pay app rates instead of carrier roaming charges.

There is no account to create and no subscription. Open the app, pick a country, dial. Every new user gets one free minute to test call quality before paying anything.

Minutes come in one-time packs starting at $1.99 and never expire. Billing is per second with no connection fee, so a 40-second call costs 40 seconds. Rates start at $0.03 per minute for popular destinations.

The person you call does not need Telvio installed - it works like a normal phone call and reaches any number, including landlines. Telvio is available for iPhone, iPad, Mac and Android, with the interface in 27 languages.