Need Help Finding the Right Users - US Healthcare site

I'm creating a healthcare price transparency site and do not know how to find the people that can benefit the most. I know that healthcare consumers can benefit from more pricing info, but many don't know what's out there.

slidingscale.healthcare # U.S. hospital financial assistance qualification
directpay.healthcare # U.S. cash-pay rates at hospitals
https://www.ClinicPriceCheck.com # main site with pricing by services, health provider quality data and more