You don't need to purchase anything to get a good look at ProTools, you can simply download PT Free. Granted, this version is buggy and comes with plenty of sound distortion issues, so I would says that it is priced fairly. Sound distortion can be minimized with a few tricks, but it is a great intro to PT.
PTLE, which is Pro Tool Light, also comes free with the Digi 001. And it probably should, since that is the only piece of hardware it will work with. Digidesign has a propietary i/o called Direct i/o and unless the software supports Direct i/o, it is not usable with Digidesign hardware. Logic Audio is the only other software that supports Direct i/o, as far as I know. the Digi 001 can be used with other audio programs, but only 2 chanels. This is because a WDM driver for 2 channels comes with the Digi 001. It is not much, but at least it is something.
So, what did you buy? Did you buy a full
ProTools 5.1 version that is for Digidesign's highend TDM systems? If so, you may need to spend another $10,000 to get the proper hardware to run with your software.
Perhaps, you purchased an upgrade for PTLE (version 5.1) which costs about $50. It is usable with an Audiomedia card. This upgrade was actually meant for PTLE users who had the old version of 5.0.1 and the upgrade was not free because their system was over 6 months old.
Their is one more option, you could have bought the a CD version of PT Free for $9.99 + shipping. I did this because my modem was so slow. Anyway, can you specify which Pro Tools you bought?