Put together a bit of Groovy code that will traverse your iTunes Mobile Applications directory and extract the metadata for each download. The aggregated metadata is exported to a csv.
Lots of interesting stuff in there. Looks like I currently have 60 applications downloaded (I tend to delete apps from iTunes that I’m not interested in) and have spent about $60. Most of the applications are free with a few larger ticket iPad application purchases.
The code has been posted to gist.
Unfortunately it does need to be run on an OS X machine right now in order to get around some conversion issues between binary and text metadata formats. That may change at some point.