Good display ad network / affiliate / advertising program to monetize finance/trading game

I may be missing something, but why not become an affiliate of TD Ameritrade or Schwab or some sort of other online brokerage?

I remember many years ago before I got into trading properly, I did some paper trading with Think or Swim, which was later acquired by TD Ameritrade. It stands to reason that if I am correctly understanding what your site is all about, it's essentially like a paper-trading-esque game. But IDK how much of it is rooted in fun vs. sound stock picking / investing principles. This recommendation I'm making is from the standpoint that people feel after using your site and doing well that maybe they should try their hand in the "real" stock market. And if that's the case, the hook for an online brokerage is quite simple. Something to the effect of, "Wow, you did so great in this game; just imagine if you'd done that IRL with your actual money -- you'd be a rich mofo!"

I did some looking and I'm not sure that TD actually has an affiliate program, but I checked my old Commission Junction account and it looks like Ally does: https://imgur.com/a/OlI6akY

Again, I could be totally off-base with what your site's actually all about, but to me, you will almost always do better to become affiliated with a related offer that you personally believe in and genuinely would refer friends to than whatever drivel gets dynamically served up by an ad network. So whether that's an affiliated brokerage or course on value investing or day trading or whatever.

Hope this gives you some ideas; let me know if you have any Qs in this area. I am by no means an affiliate marketing expert, but spent a lot of years on the fringes of that space.

I think this actually has great potential, especially if your pageviews are as good as you say they are. Have you considered letting users place actual trades on the site? That might be more lucrative than just ads. That being said, you could probably look at commission junction for relevant products. You could also do affiliate programs for various brokers like E-Trade, Robinhood, etc or other banking products. Hell, entire startups like Nerdwallet or CreditKarma are based off of selling affiliate links for banking services. Though many of those affiliate programs are not public, so you may need to cold outreach marketing people or snoop around to get an invite.