How do you approach marketing for a platform that requires two types of interdependent users.

I'm developing a platform, which I will reveal on IH soon. This platform requires two types of interdependent users. While as a developer I 'm confident about all the technical decisions, I am completely new to the area of startups, marketing and business in general. Do you have any suggestions for very low cost, gradual and effective marketing methods?

Challenges:

Maintaining a good ratio between the two types of users (This is essential)

Graduality: At the initial phase, my objective is to have a relatively small group of very interested users to get extensive feedback and fine tune the platform.

Affordability: As a college student bootstrapping this, I don't think I need to say anything else 😅.

I appreciate any insight on how this can be approached.

Just brainstorming:Just go to a bunch of relevant subreddits and manually induce word of mouth?