I just thought of another often overlooked resource - that is actually one of the best resources and it doesn't cost anything - the *perldoc's*. Perldocs is perl documentation that is included when perl gets installed on a machine. To start just do

   perldoc perl
[download]

at a command prompt. You'll see a listing of perldoc "sections" along with a short description of each section. From there if you wanted to read the 'Perl Introduction for Beginners', you would do

   perldoc perlintro
[download]

HTH.