I think there are many ways to compensate moderators without paying them a regular salary.  You can offer them free advertising on your forum if they have a business.  If your moderators are looking for business references to help build their business, you could provide them with a quality reference if they do quality work for you.  Around the Holidays if you are able, you could give them a little cash bonus.

What are some other ways/

To be honest, I really don't think moderators need to be compensated.
When you get moderator status, the feeling of having those powers is enough compensation.