I am playing Monopoly Hotels, and like all free-to-play iOS real-time games (think Farmville, etc), you have a regular currency (Monopoly dollars) and a premium currency (Monopoly gold). I know I can get gold by paying real-world money, but I would like to avoid that.
The game gives you some gold to start with, and then you periodically earn more. I thought it was through levelling up, but my last level-up didn't get me any gold.
What is the in-game free way to earn gold?