The license is free but you need to register and then apply for it on their website. The odds of causing irreversible and permanent damage are pretty small but they do exist. Like mossback said, if you’re afraid of messing something up, be sure to back up all the control units and then stick to the documented modifications. If you’re feeling adventurous and don’t mind poking around, you want to have an idea what you are changing and a way to verify said changes because what might do one thing on an F150 might do something different on an Expy or Navigator.