Arms Dealer

The Arms Dealer is an NPC vendor that will spawn once the following criteria have been met:
 * There is an empty house.
 * You have one Gun or Bullet in your inventory (not just stored in a Chest).

The easiest way to acquire a qualifying item is is get the Musket by destroying a Shadow Orb.

If the Arms Dealer is killed, he will only respawn if the above conditions are met again. This means you must place a Gun or Bullet in your inventory. Having them stored in Chests will not fulfill this requirement.

Items sold
Once the Arms Dealer has moved into a house, he will sell the following:

Note: As with all NPCs, right-clicking an item will allow multiple purchases rather than purchasing one by one.

Trivia

 * The Arms Dealer is very arrogant compared to the other NPCs and seems to have an observant personality, often noticing you (apparently) intend to either buy the Minishark or steal one of his weapons. This, when coupled with the way he speaks, may support that he is based off the traditional gunslinger from old Western movies. He also seems to have a rivalry with the Demolitionist, as he says his products are better than "fireworks".

Quotes

 * "Keep your hands off my gun, buddy!"
 * "Hey, this ain't a movie, pal. Ammo is extra."
 * "I see you're eyeballin' the Minishark... You really don't want to know how it was made."
 * "Don't bother with [Name of Demolitionist], I've got all you need right here." (Only if Demolitionist is present.)
 * "What's [Name of Demolitionist]'s problem? Does he even realize we sell completely different stuff?" (Only if Demolitionist is present.)
 * "Make it quick! I've got a date with [Name of Nurse] in an hour." (Only if Nurse is present.)
 * "I want what [Name of Nurse] is sellin'. What do you mean, she don't sell anything ?" (Only if Nurse is present.)
 * "[Name of Dryad] is a looker. Too bad she's such a prude." (Only if Dryad is present.)
 * "I heard there is a doll that looks very similar to [Name of Guide] somewhere in the underworld. I'd like to put a few rounds in it." (This will be the only message available if Skeletron is defeated, but Wall of Flesh is not. This can also be used to see the next Guide's name if the old guide is dead.)

Only during a Blood Moon:
 * "I love nights like tonight, there is never a shortage of things to kill"
 * "Man, it's a good night not to talk to anybody, don't you think, [Name of Player]?"