This would have been nice when I played Runescape back in the day. I need to make a video one day, but pretty much had the coal market cornered. I could buy out anyone that was selling coal with the amount of gold I had and could sell as much coal as someone wanted (as long as they were willing to pay my price) and still have plenty of coal left over.

I made enough gold doing that to have been able to easily pay the monthly subscription fee with some money to spend on other games as well. I'm sure their was a 3rd party market for runescape gold back then, but just being in middle school I was completely oblivious.