Hi Eliz,

They can make money from advertising-note the banners on many of the free message boards. Some also sell scripts and give away the message boards to pull in new customers. And then there is always the pay to upgrade so you can get all the bells and whistles. You may want to be able to control the advertising, customize your board, and even sell advertising when you start to get a lot of traffic. In this case you're probably best to go with WebBBS. I think it cost around fifty dollars to register it. Also if you don't have your own webhost, WWWboardpro will host it for a small fee. Just make sure you get the pro version. The regular version is from Matt's scripts but I don't think you have all the control as with the PRO version and they can't host it.
From my point of view though, WebBBS is the way to go.

Hope this helps,

Tom