What I don't like from this site is that the site owner gets part of the cut.

Should just make your own site, would that cost less? OR would using this site be more profitable?

You can make money off of ads and selling content at full cut with your own site.
But, this one you can only make money with what you put, plus the owned gets part of it... doesn't seem like a good idea. Would force people to set their prices higher just to get what they want.

I might sign up and sell stuff, if I find out which is more profitable.