Hmmm. Been quite awhile, but I think we've always played once per turn... but then I remember there being too much money, too.
Yeah, I'm pretty confident you should be getting money only once per round. How do you think that would affect your view of the game and the most popular review of this game on the Geek?
EDIT: damn the rule book is badly written in this instance:
1. Determining Income: The youngest player spins the income spinner. Each player adds that amount to the gold on his gold display, to a maximum of twelve.