Hi,
What exactly do your clients need? Do they need a knowledge base with articles or a comprehensive help? Do they want lots of users to create and edit content or just a few?
If you really need a knowledgebase solution, I would look towards a Wiki. For instance, both Mediawiki and Dokuwiki are very powerful, mature and free. You can also restrict the viewing and editing to only a handful of users if you require that. But without a good idea of what the requirements are, it’s hard to say which solution is best for you.
Greet,
Willam
