One of the best ways to make free calls is VoIP calling. Unlike traditional landline or cellular services, the VoIP phone system uses the internet for making and receiving calls. So, you can make calls for free to international or local numbers if you have a good internet connection.Callers need apps or software to facilitate VoIP unlimited international calls. Some apps, like WhatsApp, Google Duo, Facebook Messenger, and Skype, are free and ideal for personal use. You can download the app, create an account, and start calling. The only charge involved here is your internet charges.However, such free apps are not suitable for advanced business needs. For this, you need subscription-based unlimited calling plans with additional functionalities, such as the VoIP plans by Ringover.