I rolled across this one in the forums earlier and wasn't sure what to think. We've seen plenty of overpriced apps floating though BlackBerry World over the years, but this one has to be a mistake. Honestly - there's no way a developer could knowingly price a voice recorder app at $599, right?
Audio Note Taker looks to be a simple note taking app for both voice and text, touting the ability to take voice notes and record audio at the same time. It does look like a pretty cool app with some good functions like sharing and Remember integration, but I'm not ready to shell out $600 to find out. It is built for BB10 however so I'd assume that it works pretty well.
I'm going with the theory that it's a mishap and should be around $0.99 like all the developers other apps. We'll check back and see if the price drops in the next few days to be sure.