The basic version of Skype is free and allows users to make voice and video calls to other Skype users over the internet, send instant messages, and share files. Additionally, users can make voice calls to mobile phones and landlines through Skype's "Skype-to-Phone" service, but this typically requires purchasing Skype credits or subscribing to a calling plan. While the basic video conferencing features are free, Skype also offers premium features and services, such as group video calls and the ability to call phone numbers internationally at lower rates. These premium services are available through Skype's paid plans and subscriptions.