Stand Alone Software and a Plug-in for popular graphic applications

Hi, I am trying to make up my mind whether to purchase before the 80% discount sale is over. I am curious whether the statement "Stand Alone Software and a Plug-in for popular graphic applications" which appears on the home page means what I think it means. Can I use this application without owning an expensive graphic application such as Photoshop? Or, if I opted to purchase Photoshop Elements instead of Professional, would Filter Forge work with it? Does it make a difference whether I purchase the Basic, Standard or Professional edition of Filter Forge in terms of whether it will work on it's own or with less expensive graphic applications. Does anyone have any other recommendations for alternatives to Photoshop?

Thanks!