Haha, now what does that mean? What a mean is a free forum software which you can build a paid forum like D.P.? Any idea?
Wait, what do you mean paid forum, like with subscriptions? You can always use like myBB or punBB, they are the free versions of vBulletin and IPB.
But I still think you should pay 160 bucks or 80 bucks for the VB license I hate the free forum software, it makes me sick!
Makes you sick? Why? Because it's open source? Waste your money on a vBulletin license for $169 when you don't even know what you're getting in return eh?
go for phpbb it has every mods that vbulletin has but you have to customise your self takes time,headache too.
Use SMF - (Simple Machines forum)... Very reliable and has all the features that every other one has, also it can create a bridge with joomla, mambo, and drupal hosting. By far the most useful website!!!!!: en.wikipedia.org/wiki/Comparison_of_internet_forum_software This will show every forum software out on the net, and tell you all the info about every single one. Enjoy and hope this helps