Moodle is a unique version of a learning management system (LMS) in that you don't pay for a subscription to use Moodle as you would with hosted LMS software (such as Blackboard or Bridge). Instead, to use Moodle, you typically download the latest version from Moodle's download page, then install the software in a hosting environment you've set up for hosting the software. As an alternative, you can do a Git install from your hosting environment following the instructions Moodle provides for going that route.
Moodle is highly extensible and built with flexibility similar to how WordPress and other popular open source software applications are built. The core functionality of the Moodle LMS (referred to as Standard Moodle) is contained in their published download. Once you've installed Moodle, you can extend the functionality of the system by installing any of the nearly 2,000 plugins available in the Moodle plugin library.
To use open source software such as Moodle, it is best to have dedicated technical staff who can competently handle development and hosting environment tasks. For people, companies, or small organizations who don't have DevOps know-how, installing and using an open-source learning management system like Moodle is probably going to be too complicated and require too much management overhead. In those situations, it's better to shop for a hosted learning management system instead.
Benefits of Using Moodle
Moodle gives users a lot more flexibility than proprietary, hosted solutions. With Moodle, you can use only the essential features that come with the Standard Moodle default LMS download, or you can install and take advantage of any of the thousands of plugins that are available
Because it is open source (which makes the software itself free), Moodle pricing is dependent upon your hosting environment and whatever deal you have set up. For companies who have their own data centers and hosting, the additional cost of hosting a Moodle installation may be negligible.
Also, the open-source plugins in the Moodle plugin directory are free.
For the most part and with some caveats (mostly hosting costs), Moodle is free to use.
However, there are costs associated with hosting a Moodle instance, and there are also premium Moodle plugins available for purchase. Moodle pricing is flexible, and highly related to your hosting environment and whatever features you need.
Because of the open source nature of Moodle, its learning management system comes with a large community of participants in both the development of the software and advocates for advancing the usefulness of LMS software generally.
Moodle has language packs that can be installed on the core software package to support over 100 different languages to one extent or another. The world's 20 or so most commonly spoken languages are supported 100% with Moodle's language packs.
Disadvantages of Using Moodle
Moodle is one the most popular (if not the most popular in terms of number of users) learning management systems available because of some of the reasons mentioned here. However, Moodle doesn't work for people and organizations that are not interested in handling all of the configuration and hosting requirements associated with installing and maintaining Moodle.
For those who want to simplify how they use a learning management system by simply paying a monthly fee for hosting and for the system itself, Moodle doesn't make sense.