Assumption - You have a competitive product. You need a marketing/distribution support to get in front of the customers.
Medium to reach potential customers could be anything depending upon the target audience - Social media, Blog, Newsletter, Email, Web platforms like Indie Hackers or Starter story etc.
Get in front of potential customers? $0.
I don’t trust for a second that any of whoever you would get in front of, would turn into an actual sale for any hope of an ROI.
If you believe otherwise, put your money where your mouth is and instead charge a commission on the sales you bring. Then, your cut could be thousands, tens of thousands if you found the right customer. And all you have to do is what you already said you would.
Don’t operate that way? Why not, don’t believe in your own service? Why should I?
Yup…