Open source software is free.
Anyone can download open source programs, run them, copy them and pass them on to friends and colleagues without paying a license fee and without breaking any laws.
However, cost is not the most important point. Open source advocates say the word free should be regarded in the same context as ‘free speech’ rather than ‘no payment’.
This freedom means that users can change the program to suit their own needs – something that is illegal with most other forms of software. The only stipulation is that the same set of freedoms must be passed on.
Altered open source programs must be made available to everyone. The logic of this approach is that control is decentralised – so the software is continually improved. At the same time, having large numbers of people looking at and improving on programs means that bugs are quickly eliminated – so quality control is improved.