On one hand, I love free stuff, and if there weren't any paid skins I would not miss it in the least, but, seeing as I'm a fellow artist I 100% support getting paid set commissions for one's art, as that is the very definition of being a professional artist!
If it were left up to the customer, then you would not make any money, as the general public can be a spoiled entitled petulant child at times... just ask anyone in customer service!