Haven't MS allowed multiple instances on their Office Home package? Can install onto 3 PC's I think.
However, there are Open Source alternatives to nearly everything. OpenOffice, GIMP, Linux ...
For the speed limit, as its another can of worms, it doesn't matter, the point is you are still over the limit. In fact speedos read 2-3mph MORE than what you are doing in most cases.
The Steam system is a good idea from that point of view, however, imagine downloading like 1GB of Microsoft Office 2007 Pro each time you want to use it somewhere different.