"Mobile is not an easy platform. It has lots of constraints that normal PC's and the Web do not have to deal with, and so it's harder to train qualified devs for it still." Personally, I find it much easier to do development for iOS than for regular Mac OS X. Yes, there are constraints and the workflow is quite different, but once you get over those I have found it to be a much easier system to understand.
* Clearly defining your business goals.
* Hiring someone experienced and trustworthy.
* Letting them guide the implementation.
I hate working for clients that insist on wasting their money. It makes me feel dirty. I would much rather work with a smart client where we can build a long term relationship because our first projects are susccessful, not disasters.
My company does mobile development (see profile for email) all day long.
The issue is letting your dev tell you what can be done inexpensively and starting with that. The hourly ranged mentioned in the article fits exactly what we charge (although on the lower side), however the time required is way off base. If you come with fully developed wireframes, etc, they're sure to include 3-10 things which would take quite a bit longer than an alternative, or will contain lots of things better put in a version 2 product. What you want is no approval requirements based designs with a developer you like the past work of.
Mobile is not an easy platform. It has lots of constraints that normal PC's and the Web do not have to deal with, and so it's harder to train qualified devs for it still. However, the projects created on this platform can be done economically with the correct guidance.
If you try to run the project too completely, try to be too involved, you can very well get the prices and timelines in that article.
Even if you have the cash to spend 30k on the App: My suggestion, get something done for the 7-10k range which satisfies part of your original vision, release, then work on adding more. Iterate on the design you got in the first version, after you can get solid quotes on the changes in it, and after you have some revenue to justify additional expense.