well it would be best if you use apps because now these are many apps which make this is very cheap like i am using meeting mogul calling app which makes my calls very easy & cheaper rates to anywhere i want to talk it is quite easy & very suitable for me to use this app.
A mobile phone is a wireless handheld device that allows users to make calls and send text messages, among other features.
OPPO F5 (Black, 64 GB)
Samsung Galaxy S8 (Midnight Black, 64 GB) (4 GB RAM)