It is free :
http://www.microsoft.com/en-us/bi/powerpivot.aspx
I have analysed lots of BI tools, which could be useful in your scenario, but most require a bit of technical / database knowledge to iron out wrinkles.
The 'R' programming language is pretty useful for statistics and could be used to aggregate a lot of files (and its free). Also if you want to generate dynamic reports using templates then you should look into sweave which is a package in 'R'. (http://www.stat.uni-muenchen.de/~leisch/Sweave/) You could build beautiful PDF reports that you simply run a script to generate if they are easily created into a template. But that would also require learning Latex for creating documents, something that is used heavily in the academic world but I have yet to see it in the business world.
Another approach which I would try is to use a programming language to dump it into a relational database and then use SQL to access the info (which is heavily used in business setting). This option also also allows for others to use it with familiar business tools. My unconventional tools of choice would be Ruby and using Rails to build an interface.
Most data has a physical location associated with it (street address, lat-long, something mappable). "A picture is worth a thousand words". Mapping data can help you visualize and mentally process heavy data loads. And Excel is one of the database formats typically compatible with standard software so with a smidgeon of luck you can probably kind of plug and play.