I think that every developer has sat around scratching their head on this one before.  How do you recoup your hours of hard work and code crunching once your app is out of beta and ready for the world?  This article I ran across on Vitamin takes a look at this and offers up some suggestions.  Granted, it's harder these days to put a price on a piece of software when the world is used to free, free, free...  thanks Google.

Link to Vitamin Features » How to price your web application