Merchant

The Merchant class, specializing in farming and money generation, offers many skills to achieve those aims. From being able to improve buy and sell prices to and from NPC shops, all the way to a spelunker buff, and even setting up a shop stall on multiplayer servers.

Unfortunately, they gain only one attack skill which costs coin to use and has a relatively long cooldown. They are best suited to getting geared up and supporting costly gear for large parties.

The quest to become a merchant starts at level 10 from the Merchant. The quest is 2 parts. Acquire 1 gold coin and move out west.

Name	Effect	Cost/Cooldown	Requirement
Discount*	Lower buying price at shops 1%, 2%, 4%, 7%, 10%, 13%, 15%, 18%, 21%, 24%	Passive	Coin Speciality Lvl 3
Overcharge	Higher selling price at shops 1%, 2%, 4%, 7%, 10%, 13%, 15%, 18%, 21%, 24% Approx -1% per level, down to -10%	Passive	Discount Lvl 5
All my Loots	Increases the chance of getting double loot.	Passive	Coin Speciality Lvl 7
Coin Speciality*	Add a chance of making monsters drop additional coins when hit and/or killed. 2% per level, up to 20%	Passive	None
Toss Coin*	Toss a coin at the enemy to deal damage. 117.3% damage +7.3% per level, up to 183%	5 second cooldown, consumes 10 Silver per use.	None
Merchant's Eye	Scavenger status 1 minute duration / level	30 mana	None
Open Stall	Opens a shop where any player can buy it's items Does not work at this time.	None	Overcharge Lvl 10

1: Discount does not stack with Discount Card, however it does allow a merchant to sell items (such as the Terra Blade) for 24 gold, while purchasing them back to only 15.4 gold, allowing infinite profit to be made. The largest profit I've found comes from 99 Life Fruits, which sell and rebuy for about 50 Gold profit per stack. This applies to every item you sell, as the discount is applied to the repurchase price, which was originally your sale price.

2: Coin Speciality, oddly enough, seems to work on Statue mobs on occasion, allowing infinite AFK money generation.

3: Toss Coin launches ten silver coins in a random spread (largest seen about 60 degrees between outer projectiles). Unlike other attack skills, the damage does not appear to be altered by equipped weapon, but the damage does appear to be Melee (tested with X Emblems) and can be boosted by the standard means. Even at its highest level and boosted as high as possible, it's not worth using against hard mode monsters.

The Merchant, like the Fisherman class, is arguably best suited to an alt. Even at medium levels the Merchant can be used as an infinite money generator by simply sell/buy cycling a single item stack ad nauseam, and they don't really offer anything more after that asides from infinite Scavenger's Eye.

Since the Merchant is only 5 skill points short of maxing out its entire skill tree at max level, a guide is largely unnecessary, just upgrade Merchant's Eye when you've nowhere else for your points and raise your gamebreaking Discount/Overcharge skills as early as possible.

Final status bonus

Status	Bonus
Strength	+12
Vitality	+10
Dexterity	+7
Charisma	+5
Agility	+6
Intelligence	+6
Luck	+11
Wisdom	+2

Update from Arendeth here is info I gathered for N Terraria 6 for the merchant

Max level 30 note for stats use a warrior like build of str and vit Coin Power Description: you gain different bonuses based on their coins, and stack coin slots. Only valid to coins in the coin slot. Type:Passive max points 10

Axe Mastery Description:Turns Part of the weapon's (sic) axe power into damage. Intial Boast as 12% percent adds(sic) 3 percent more boost per skill level.

Open store: 1 point given free after getting coin power to rank 5 description you can open a store to sell to players

Backpack mastery Description:You may use an alternative way of stashing items. Increases            info: acts as portable bag/chest like safe and Discount Makes Shop prices fall 2% decrease per skill level max 10

Makes shop items cost more. overcharge Bonus 2 coin per skill level max 10 needs discount at 5

Coin Mastery Throws Several Coins to cause general damage 15s cooldown?

for class next recommend the warrior from the guide after maxed to class level 30