I prefer to think of merchants as more like vending machines and pawn brokers. In the first situation, they provide you with something you want (a cola), right when you want it, but it'll cost you an extra $0.50 over the price you'd pay at the supermarket. In the second situation, they'll take something you don't want anymore (like some old antique junk in your attic) right away, but they give you less money than the sale price. You should be happy that merchants do what they do despite all the crap they get from people like you who scapegoat them. It's because of merchants that you can sell 50 coal that you picked up to the GE instantly. If it weren't for merchants, you may have to wait hours for someone to come along who wants to buy coal for smithing. It's not profiting from someone else's loss; it's not zero sum. The merchant may make 4% profit, sure, but both the seller and the buyer get convenience and save time. Plus ANYONE can merchant if they want to. Completely fair.