I'de be interested to see the difference between what people say they pay for apps and what they actually do. I imagine it isn't $3-5.
The people who participated in this survey are people interested in journaling apps and the Quantified Self, so they don't represent everyone. Maybe people interested in QS spend more on apps?
This was just a rough survey, mainly so we learn more about our customers. We just thought it was interesting and worth sharing :-)