Coin
To use your gold at the bar you need to turn it into a coin. Well, more than one coin, probably. But you know for sure that you can make at least one coin out of the gold you have.
せん
ぜに
None
You use the coin to pay a centaur (せん) at the bar. The centaur is the bartender and he makes special drinks for those who pay in gold coins. Good for you!