Invision Free is the free version of the Invision Power Board forum software.  Currently, Invision Power Services is beta testing version 3.0.0 for release later in 2009.  Invision Free ends with version 1.3 and was the pilot platform that started the evolution of the current stable version of Invision Power Board.  Invision Free is the barebones, basic version of the forum software and is widely used by those who do not want to invest the money, time and effort into installing, upgrading and maintaining an Invision Power Board forum.  Invision Free also comes in a hosted version via the IF web site, where they place ads on your forum and you have limited resources to use when utilizing a forum with them.

Invision Free 1.3 is considered open source software.  This means anybody can download, install, modify and use it as long as they install and take liability for using the software on their own web server.  Invision Free does not support, modify or help with issues that pop up if you host your own IF forum.  However, you are free to do with it what you will, and this includes content, modding and other changes to the source code behind the forum software.  Invision Free will charge a fee if you want to preserve and install the database from one of their hosted forums to one you host your own.  However, this fee is relatively low and the turnaround time is quick.  If you want to transfer your forum from free to a hosted service, paying Invision Free for database retrieval and conversion is worth the price.

Installing Invision Free is relatively easy.  You want to download the software bundle, extract it and then upload it to your web server.  Once uploaded, you want to open the installation instructions and change folder permissions to be executed and written over.  Simply follow the installation dialogue, click Start Installation and IF will walk you through the process with little input from you as the installer.