"Noooo, why would a merchant ever exaggerate prices, besides you already bought it with no complaints so you can't do anything now, as for the medkit, you're right, it shouldn't be that expensive, but due to supply and demand, especially since you have 8 people going off on an adventure where injuries are certain and the demand for meds will be high, the price of the supply is also, you guessed it, high. Now pay the 40 gold or get out of here."