We’re a small startup trying to figure out how to get people on board for a pilot project (at no cost)

As I mentioned in the post title, the question is: HOW do you attract your first users for pilot testing? We have a budget covering office space, development, and salaries for 8–12 months (which isn't bad at all), and we do have a marketing budget, but it’s limited, and we don’t want to burn through it without seeing results. Does anyone have concrete ideas on how we can attract our first companies? We aren't looking for average end-users; we need actual companies where we can discuss everything in detail at the founder level. Maybe we’re missing something—please share what methods have worked for you.