All of the perl downloads available from this page are freeware.

If you will be running perl on a Unix/POSIX system (or Unix-like system, such as NeXT, Plan 9, AIX, and so on) you can download the source code for perl from Perl.com

If you will be running perl on a Win32 (Windows2000 or 95) system, you will need to download the latest version from ActiveState.
Follow the links on this site to the Win32 download.

If you are using a Macintosh, you can use Matthias Neeracher's MacPerl port for the Macintosh.