Mercantile Douche

A person who is incredibly annoying as a salesperson, clerk, or bartender. Someone who is a douche about how much they are charging for something.

Charging a lot of money for something is not what qualifies an individual as a mercantile douche. The individual must get upset and defensive when you challenge or inquire about the pricing schedule of their product. Basically they will be a dick when you ask about the price of something, and act like they are personally offended by your question. This description of an individual is especially poignant when the individual that is acting as a mercantile douche is not the individual who sets the prices or actually receives increased revenue from the pricing schedule.

Bar Patron: "Hi sir, why does this IPA only get a 12oz pour but the pale ale is 16oz?"
Mercantile Douche: {launches into lengthy diatribe about the cost of brewing beer and state laws about alcohol consumption. also uses condescending tone and has hipster mutton chops}
Bar Patron: "Geez man, I was just curious... I'll take a pale ale"
Mercantile Douche: {ignores social cue from patron that he doesn't want or need the lecture and continues his butthurt speech about why you should pay the same price for less on the IPA, eventually does poor beer}

"Wow, I just asked that bartender why the IPA cost a dollar more than the pale ale. He got super butthurt about defensive and started lecturing me about the cost of making beer. What a Mercantile Douche."