Computer users typically pay for expensive software when most of what they need can be obtained free of charge. This free software is known as Open Source.
According to the Open Source Initiative, Open Source software must meet specific criteria. First and foremost, it must allow for free redistribution; its source code must be made publicly available and it must allow derived works and modifications. There is actually a long list of criteria, but those mentioned are the basic guidelines.
This means that a community of users can come together to create a program in an open manner, making for a better computing experience for everyone. It’s actually a very large community which pumps out every kind of program, from productivity to music to video to games, and all of it for free.