Use http://Meetup.com + attend Meetup events in your niche.

Network with organizers.

Be a guest speaker.

I've use this method anytime I'd like to test any part of a new or existing business...

Or bootstrap a new client list with people with tendencies toward big ticket prices.

Way more lucrative + easy for bootstrapping, then any paid mechanism I've used... since starting my first business in 1974.