Some years ago, the former STSC, distributed a freeware version of APL, known as APL Special Edition. It's release notes included the following: "You may use it without charge, copy it, give it to another person, place it on an electronic bulletin board system, or distribute it in other ways without requiring payment from the recipients." I've preserved a copy in FreeAPL.zip.
Download PLJTools.zip. Install DOSAPL.FON into the Windows font directory. It adds two APL fonts for using DOS under Windows. The zip file also contains a few workspaces to get you started.
Please send your feedback to:
plj541@gmail.com