It's only free if you have a free web server with free bandwidth and free database access. You still have to pay for hosting. (Unless you host it at home, in which case, you're paying your ISP and likely violating their TOS and AUP) Generally what you are paying for with a script like this is the ability to commercially sell mass forums, or to give them away free and support it with ads. (inivisionfree.com I think does this?) There is almost no reason to have a script like this unless you intend to make money off of it, so they tend to be not free
-Drakkim