Man, some people just want everything for free. This is not a matter of charging for skins, it is a matter of subscribing to avoid advertisments. Every skin site does it, and it is completely optional. Futhermore, WinCustomize doesn't plan to have pop-up ads at all. They are hoping enough people will subscribe that non-subscribers won't need to have pop-up ads thrown at them.
DeviantArt, for example, is $30 per year. As far as I know, that gets you access to some members only skins and the luxury of not seeing ads.
So, Stardock wants to offer all that and more for $20 per year and people start crying about it. Jeesh, if you don't want it, don't get it. But everytime you come here and don't have ads thrown in your face, just remember: it's those of us who chose to sign up for this expanded service that are paying to keep pop-up ads off your screen.