I develop an educational app geared for kids and just like some of the people here. I dislike ads, in app purchase, external link etc so I made sure that my app doesn't have any of those and price it at $0.99. I keep updating it based on user feedback to make the app better.
It's good to read that there are a lot of parent here that say they won't purchase any app with ads and/or inapp purchases for their kids but I think majority of the people don't care.
Most of the top 15 apps in my app category/subject are free with ads and/or in app purchases. They can afford to make it free because they make money from ads/in-app purchases and because they're free they get a lot more download that keeps their ranking higher burying app like mine.
It's hard to compete in that kind of condition but I for now, I can't see my self using ads/in-app purchases in any of my app. I will try to compete by bringing better qualities apps.