I came across the Evidation app (formerly Achievement) a few years ago. I earn an average of $10 (in cash) every 6 months that is direct deposited into my checking account. All I needed to do was link my FitBit device and login to the Evidation app and I earn points on my steps, heart rate and exercise achievements. I also earn points when I log my eating and weight within the FitBit app.
I learn about up to date health information from Evidation and earn points by taking quick health surveys in which they use for health research studies.