Business models for open-source software
Software companies focusing on the development of open-source software (OSS) employ a variety of business models to solve the challenge of making profits from software that is under an open-source license. Each of these business strategies rest on the premise that users of open-source technologies are willing to purchase additional software features under proprietary licenses, or purchase other services or elements of value that complement the open-source software that is core to the business.
Source: Wikipedia — Business models for open-source software (CC BY-SA 4.0)