Virtual Precious Metals Trading

I realize that this could probably be better addressed in one of the other forum topics but I wanted to "pigeonhole" it so that newbies (to paper trading) like me could have a place to begin their education.

As a "physical stacker" I am interested in learning the basics of trading and would like to know what "virtual" PM trading sites members used (or still use) to "get their feet wet". Thanks in advance for any and all suggestions.