Daneos you have to know about this!
So after I hunted down some monsters around North Parunga Rock (Excuse my possible misspelling), The shop keeper Qui Ning glitched with me.
I was selling pieces of armor that are worth 1522 coins! The game lagged for 30 seconds, so what I did is press the Sell button a couple more times.
Later on, I was disconnected. When I came back, I got over 4500 coins!
I don't know if the glitch happened because of disconnecting or a bug so I have to let you know!