Although I agree in concept with the "free" PDF, the book is part of the BBU serices and doing so would deny the authors of their royalties. Slaughter & Delwiche have done an excellent job and deserve their royalties.
Under the SAS Academic Program, SAS will provide pdf's of the course notes and a PowerPoint slide set, as well as a substantial price discount on the notes. I've used all in my course at various times. Because my teaching has been done in concert with a biostatistics class, the order of presentation is vastly different from either the SAS course notes or "the little sas book" so I've not been able to rely totally on either.
I've been using EG since 2002 for a class on managing research data. What I like about it is that I can encapsulate data and sample procedures in project files for the interactive part of the class and avoid all the wasted time that used to be spent on typos and navigating to folders etc.
If the topic for the day is SQL joins, for example I don't want to get bogged down in having some of the students mistype a path in a libname statement. I can set up a project that parallels the PowerPoint I'm using for the day and the students can have the example datasets right at hand.