Clown Hat

The Clothier will not carry any of this until a Clown has died in your world, and Clowns only turn up on Blood Moons once the world has gone into hardmode. That pushes the outfit deep into a playthrough. Budget some repair work for the unlock too, since the bombs a Clown throws will punch holes in whatever you built while you fight one.

Hat, shirt and pants are appearance only and go in the social slots. The stock stays in his shop permanently once it appears, so there is no reason to rush the purchase. It suits a circus or carnival themed build, and the hat on its own carries the look well enough if you would rather keep the rest of your vanity outfit intact.