Well Blackberry OS applications can range from a few kbs, to a couple mbs.
You can't really classify them into categories, e.g. games use more than business applications, because it just depends on how in depth they are and what they do. You could get a simple game such as a simple version of Tetris, an it could be only around 500 kbs. However if you got, say, a racing game, that would be more complex, it might be around 1 to 1.5 mbs. Another of this could be some apps. that I have, a "Quick Search with Google" - only 76 kbs, meanwhile my "Weather Channel" app. is a comparatively high 1.9 *mbs*. Now consider what the two do. The Google search app is just a way to quickly search with Google, opening up your browser once you have hit enter or search. The Weather Channel app. is also comparatively much more complex, sending and receiving very detailed, sometimes complex information and Doppler maps back and forth. So it really depends on how complex the app. is or what it does, not really what kind of an app. it is.
Hope this helped.
Greg