Ask HN: What's the best place to buy survey responses from a specific niche?

I'm looking to run a pricing survey to a specific niche (musicians) - SurveyMonkey audience isn't specific enough, and I've been struggling to find a service that can deliver me responses to a relatively long (about 20-question) survey. I'm willing to spend money, but Qualtrics is a little out of my price range. What else is out there, and what do you use?