If DB is just aften an app that utilises his current website, you can get one of them for 200-500 dollars on the websites Edwin mentioned.
If its a full on utility/game/app only app, then anything upwards of $1200
Apple has a lot of free stuff app developers can use, hence all the rubbish copycat apps.
Even if your average at changing web sites DB, you could use google IUI, find it at the coders centre you can do it yourself, and you dont need an apple mac to do it
http://code.google.com/p/iui/
can see a run of appraise my websites soon, when everyone on here has had a go at building their own lol
ADDED .. If you do the bit at iui yourself, you will still of course need $150 worth of work to get you the frame to make your site/app ready for the appstore.
I have one on my phone from a user on here, rob I think, accident app, why not ask him.