First of all the answers above are great. I say...give it away and get feed back from 1,000 users. What would they be willing to pay for the app if they had to pay? If you can't give it away, you likely cannot sell it. But, if you can demonstrate a need and more importantly a desire for the app you will probably be able to get funding. Then the more important question becomes do you want funding and how much equity are you willing to lose.

Michael T. Irvin
NoHogWashMarketing.com
"Get To The Top Without The Slop"
michaelirvin.net