WordPress is an open source software based on PHP & MySQL. Open source software is developed and managed by a community of developers. Open source software is a non-commercialized approach to developing software. The beauty of this is that WordPress is free.
The drawback is that there is not any traditional customer support. WordPress offers support in document form, but you have to search for the answers. You will not be able to call a customer service representative and ask your questions. There are also third-party tutorials, that cover beginner to advanced subjects.