Painter

He wants a vacant house and a town of eight other residents, which puts him fairly late in a first world. The count is looser than it sounds: the Old Man out at the dungeon, a visiting Traveling Merchant and any town pets all count toward it. The Skeleton Merchant does not, since he never actually lives anywhere.

His stock is split across a default menu and a decor menu. The split exists so that a single overlong list cannot push items out of reach: paint and tools sit in one, paintings and wallpapers in the other. If a pylon is available where he is standing, it appears in both, so you never have to remember which tab you left it in.

Plain color is cheap enough to repaint an entire build without thinking about it, and the three tools are a one time purchase you forget about immediately. The lines worth planning around are the specialty coats. Shadow Paint and Negative Paint wait for hardmode and do things ordinary tinting cannot. Illuminant Coating makes a block glow with no light source attached to it, and Echo Coating makes one invisible while leaving it solid, which is how hidden doors, floating furniture and secret rooms get built. Both want him standing in a graveyard, and the echo one also wants the Mechanic in town until Plantera is dead, after which that condition falls away.

Which paintings and wallpapers he offers depends on the biome he happens to be standing in, the phase of the moon, and what the calendar says. Completing the set is therefore a logistics exercise rather than a money one. None of it is difficult, it just asks you to physically relocate a man repeatedly.

The cheap method is to build a one room house in each biome you care about and then leave. Any resident whose house is off screen at night teleports home to it, so you can seed half a dozen biomes, come back the next day and buy from each in turn. A King Statue or a wired teleporter does the same thing instantly if you have one already.

Corruption and crimson resist this, because keeping valid housing intact there is awkward. The usual workaround is to build on convertible blocks, spray the surroundings until his stock changes, buy what you came for, then purify the area again. The evil powders do the same job before hardmode.

Converted biomes pay double. Talk to him in a hallowed desert and he offers the desert painting and the hallow painting on the same visit, which roughly halves the number of trips you need.

He is not defenseless. He shoots at nearby enemies with a paintball gun that scales as you progress, and there is a small chance the gun itself drops when he dies. One of his possible names is a nod to a former sprite artist, and a painter carrying that name drops a hat no other version of him will. The check reads the real internal name, so translations and resource packs cannot fake it in either direction. Most of his other names are Italian, several borrowed from actual painters.