Is it right to charge for citizen science?

I heard an interview with Brian Hare on NPR about research into dog cognitive abilities. He mentioned his dognition Web site as well as his book. The pitch that he gave was that the site provides a way for dog owners to contribute to scientific research on dog behavior. That sounded like a neat idea. The problem is that they charge for this. While it is true that dog owners benefit by seeing how their dog compares to others, it does not seem right that people should be charged for contributing to the research. I am not a dog owner, but I know several and I initially thought I would mention the site to them, but because of the charge I am going to pass on this.