We could have called it the Special Skin economy. However, from a purely economic POV, the fundamental unit of measurement on the NFT side of the economy is the Trait. In fact, from that POV, Special Skins, or snooks are nothing more than Trait repositories.
There are several ways of getting Traits. None is free. Acquiring Traits demands investment of time, work and sometimes money (although Snook is not a very welcoming environment for those who think that money alone can be a sustainable source of progress).