The pricing is pay-as-you-go. Calls are charged on a per minute basis with no connection fees or hidden fees of any kind. You will only be charged from your Roamer account when receiving calls from your home country or calling abroad with Roamer. Rates may vary depending on country. When calling locally and using the internet you will only be charged from your local SIM card balance.
Making calls over Wi-Fi/3G/4G will cost less.
If you choose to receive calls with Roamer when traveling (to avoid incoming call charges) you need to enable "Receive calls when abroad" switch in the leftmost menu. Once enabled, all calls originated to your number will be forwarded to Roamer service number in your area. Usually forwarding uses your local minutes. To know the exact rate if any, enable "Receive calls abroad" in the leftmost menu in the app, follow the instruction and after the confirmation, call your regular number from another phone. Check the balance to see the rate. DO NOT FORGET to disable "Receive calls abroad" when done, otherwise you will not get incoming calls to your regular SIM card.
Receiving calls over Wi-Fi/3G/4G with Roamer is free (incoming calls over Internet). Incoming calls with Roamer are supported in limited number of countries.