[srik]

To add to @tinylittlefish's reply here, it might also have to do with perceived value. To the user, it feels like she will be getting an app within the quality range usually associated with $5 apps, but is able to get it for only 2 bucks. Something like that.

[markchristian]

Right. Plus, the benefit of the impulse purchase is that you may gain a very vocal fan who never would've tried the app for $5.