Merchant

A merchant searches for the perfect prize, not for themselves, but to be given to someone else -- for a prize of course. Choosing this subclass means finding a roguish path that will allow for the preservation of all those things which the merchant wants to sell, including the parts of monsters that eager potion makers may desire.

Smarter Bartering

At 3rd level, you've devoted yourself to preservation of a product, and swift force in taking out any competition to gaining that product. As such, you devote using your mind to work your words, drawing on observation and intuition to convince your customer of your truth. Whenever you make a Charisma check, you gain a bonus equal to either your Intelligence or Wisdom modifier (your choice) to that check (minimum of 1).

Risk for Reward

At 3rd level, you can make conscious decisions of whether you can gain the better part of a deal or battle. On your turn, when you make an attack, you can choose to make that attack with advantage. If you do so, attacks against you have advantage until the beginning of your following turn. This can only be used once per turn, and only on your turn. 

Mercantile Expertise

At 9th level, you gain an incredible ability to identify the best prices and costs, as well as hidden secrets of any item you come across. You gain the ability to cast Detect magic and Identify at will without needing material components or a spell slot. You can use this feature as many times equal to your Intelligence modifier and regain all uses at the end of a long rest.

Additionally, you gain advantage on any Intelligence check to determine the cost of an object within 15 feet of you.

Customer Knowledge

At 13th level, your quick thinking allows you to better calculate who best to sell the proper item to. A gold ring for a rich narcissist, a new cow for a downtrodden farmer, etc. This quick thinking also gives you incredible reactions in battle, directing an attack like merchandise to someone else. If an attack is made against you, as a reaction you can make a Wisdom (Insight) check against the attacker's attack roll total. If your check beats the target, you can instead have the attack miss and can target a different target within 5 ft of you. This can be used a total number of times equal to your Wisdom modifier (minimum of 1). You regain uses of this feature at the end of a long rest.

All Or Nothing

Once you've reached 17th level, your art of weighing benefits and flaws in all forms of buying and selling, as well as in combat, have reached near peak capacity. On the first turn of combat, you can take an additional action before any other actions on your turn make an attack, and if that attack would deal Sneak Attack damage, you can choose for the Sneak Attack damage to be treated as if you had rolled the maximum amount. When you use this feature, you cannot use your Sneak Attack feature until you finish a short rest. The damage from your Sneak Attack feature cannot be increased in any way, including a critical hit or vulnerability.