It is free to call and send SMS in Iceland, regardless of what network you are with, but you pay for data and internet use.

So if you have a phone number in prepaid (Frelsi) and do nothing but make calls and send SMS then it is basically free, but you have to top up the number every three months to keep the number active.

If the number is not topped up for 3 months, outbound calls are blocked, but you can still receive calls.

If the number is not topped up for 8 months, outbound calls are blocked and you can not receive calls.

If the number is not topped up for 18 months, the number will be deactivated.
All mobile numbers can be reactivated for 1990 kr. except unregistered numbers and 4G data numbers.

If you just want to talk and send an SMS to your friends then we recommend 'Núll hjá Nova' - the service that only includes calls and texting for 0 kr. per month. It changes everything for those who just want to talk.
You just have to have a Nova number to be one of the happiest customers in Iceland - completely free!