If you’re making a case for Moodle at your school or organization, be sure to check out the aptly titled Moodle.org resource: http://docs.moodle.org/en/Case_for_Moodle.
Outlined on that page of Moodle docs is a guide to
- introducing your administrators and/or staff to open source software,
- how to frame Moodle’s cost (free),
- Moodle’s design and foundation
And more. A great place to start for anyone researching the costs, benefits and potential pitfalls of adopting Moodle.
If you’re looking for specifics about cost, you might also check out the Moodlenews Feasibility study which can provide some qualitative/anecdotal information about the real costs associated with Moodle: http://lmspulse.com/feasibility-study/