Description here on BGG includes the following:
Bills worth $10,000 for each color of bill you collect.
There are no such rules in the expansion rulebook. However, there are "rainbow cards" that Looks like they could have been the bills described above. But the rulebook has completely different rules for these cards.
I wonder what happened? Why was the original idea scraped and replaced with new rules? I think I do like these new rules better, they just fit the theme more. But I would like to know what exactly the original rules were..