Since you have access to 500 people through some sort of mailing list or announcement system, I would suggest that you hold periodic contests.
Basically, make sure that different people win at different times; don’t just award to the same small group of people every single time you hold the contest.
How can you make money with these contests?
It’s actually quite easy!
You can comment on a YouTube video that is directly related to a niche for a CPA program that you are promoting.
Make sure the comment is clear and excites the reader to enter their email address or do whatever action that the CPA program will pay you for.
Hold the contest—it can be like a $5 or $10 contest; it can be dirt cheap!
And get those 500 people to like your comment and also share the video that you are commenting on to their social media accounts.
You can even push the envelope and have them share the video on Reddit and some other platforms.
This is really just a form of parasite promotion.
You're not pushing your website directly; you're using somebody else’s YouTube video.
So if anything goes wrong, they have to go through that level—they don’t go directly to you.
This is just one idea.
The truth is, since you have the trust of 500 people, you can monetize that crowd through a wide range of social proof–type services.
You can also have them leave comments or mini-reviews that you can then compile.
The list of possibilities is endless!
The key is to incentivize them so that they stay with you, and whatever announcement you send gets enough takers.
Otherwise, you're just basically wasting your time with 500 people who don’t care about whatever message you send out.
You have to reward them at some point.