Voice over Internet Protocol (VoIP). Also Get Free WiFi to Get the Free Calls. The Top Apps are:
12Voip save money on phones
Am Voip
BJS VoIP 1
ChilliSim VoIP
Dang-VoIP
EXPLORE VoIP
EasyVoip Save on Mobile calls
FreeVoipDeal Cheap Voip Calls
G2PLUS Dialer
Hangouts Dialer - Call Phones
Idea Voip Dialer
JustVoip voip calls
LowRateVoip call abroad
MAXXVOIP Dialer No-1
Media5-fone VoIP SIP Softphone
MizuDroid SIP VOIP Softphone
MobileVOIP Cheap Voip Calls
Mr.Voip
Rynga - Cheap Android Calls
SCCPPhone Voip Softphone
Sawa Voip
TeliVoip
ULTRA VoIP
VoIP Bandwidth Calculator
VoIP.ms SMS
Voip By Antisip (+Video)
VoipCheap Cheap travel calls
VoipStunt - cheap voip
WiCall : VoIP call, Wifi call
WiCall is the cheapest VoIP serv...
Zoiper IAX SIP VOIP Softphone
easybell
Notes:
Another messenger apps are available for free calls.