How can I host my own sites for free, while charging others...

Hello,

I have a WPMS and I have my own sites on their which I do not want to charge myself for and still want to be able to charge other users but I want access to the pro features.

For instance, I want to have access to the domain mapping function, however since it is a paid only feature, unless I pay for the sites myself, I cannot use it.

For example, my site http://www.testimonialengine.com is not working (not sure why as I have set the plugin to allow for free sites, rather than a pro site only feature and as you can see it is not working)

Any thoughts?