Moodle is a good LMS with which has grown over the years and offers a host of functionality and features that are very useful to have in an LMS. Add to it the fact that its open source which makes it free to use, has made it very popular.

Moodle has been able to sustain itself and keep evolving through its community, resulting in its emergence as a good option for anyone wanting to use an LMS. But is Moodle or any other open source LMS (there are a few good ones like the ones mentioned here) really free? Though they may be free at a tangible expense level, they do carry a cost which the organization implementing the LMS should be aware and careful of.