Please Pay attention to Saba Service Details:
The direction of this service is from Iran to outside, so you can not call Iran using this service, but you will have a national number inside Iran and you can receive calls from Iran if anyone call that number in Iran.
This service is monthly and will be renewed every 30 days.
There is no hidden fee, no connection fee, no extra fee.
it is unlimited, but there is a Fair usage Policy as a home user.
Monthly cost of this service ( based on how you receive calls ) is 9.90 to 14.90 USD.