I think you are talking about playing for credits.
Skill Gaming: Ready-Go Tournaments and Match Play Challenges fall under Skill Gaming, which certain countries and US states prohibit.
The U.S. states that do not allow skill-based gaming are: Arizona,
Arkansas, Connecticut, Delaware, Florida, Iowa, Illinois, Louisiana,
Maryland, Montana, South Carolina, South Dakota, Tennessee, and Vermont
As for information, it is hard to find but if you look at the bottom of every page there are grey words that are links.
Hope that is what you were looking for.