Alternatively, make a simple web app that subscribe for $5 a month, 400 subscribers will get you the same $2k. People are more willingly to spare a $5 change.
This has a strong element of "build it and they'll come."
It leaves out a large part of the problem of selling something. How will enough interested people discover the "simple web app"? If there are competitors (chances are there will be) and the app's page is in the 12th results page of Google and PPC keywords cost $5 per click, getting enough relevant traffic to ultimately reach 400 subscribers can be quite a lot of hard (and costly) work.
As an indication, if you look at point 5 in this survey http://webappsurvey2009.techcrunch.com/ you will see that ~50% of marketing sites of web apps got 0-1,000 visitors a month.
It can be done but don't just expect to "build it and they will come."
Also, a book that sums up good points about selling a web app (especially if you are a developer) is http://www.startupbook.net/
It's got to be coincidence that 40.48% of the marketing sites got less than 1000 visitors, and 40.48% of the businesses in the survey had a single founder right?
Yup. It just comes down to value, and it depends on the app. Underpricing something that has a lot of value is generally not a great business move. Especially when you intend on adding features later.
But if it's just a simple web app, presumably one that has some similar competition, then $5 may be a better idea.
