Mark - the only difference between "academic" and "full" are the EULA's. In the academic EULA you agree to not use the software for-profit. The full version is used for commercial projects (i.e. make $$$).
When buying new, the academic version is sold only to registered academic institutions at a deeply discounted price with the EULA that says you aren't going to be cutting for-profit work on this NLE. Technologically, there is no difference between the two. Same software, same capabilities, same templates, same codecs, same import/export capabilities, etc.
As Scott said, be careful on fleabay. You don't necessarily know what you're getting (conditions of disc, serial #'s, etc.)
Ryan Holmes
http://www.ryanholmes.me
vimeo.com/ryanholmes