I don't know where the rumors came from that IBF 2.0 will no longer offer a free version. Judging by invisions site, the situation is exactly the same as for 1.0. You can use it for free if you want, but if you pay you get some additional features.
From:
http://www.invisionboard.com/download.cgi?subc=trial
Important Information, Please Read
You are about to download the free trial version of Invision Power Board. Although this version is fully functional you must understand the limits of the free trial offer:
Absolutely no technical support, including installation assistance, is provided for the free trial download. Technical support is provided for those purchasing the software by email, live chat, and telephone 365 days a year.
Your forum, although perfectly functional, will display a small notice at the bottom of the page that it is a free trial download.
Certain advanced features of the software (subscriptions manager, spell checker, chat service, etc.) may not be available in the free trial option as these require additional modules to operate that are only available to licence holders.
You can purchase a license to Invision Power Board at any time to download addons and request support and the upgrade from the free trial version is quick and easy.