You can download the unregistered software, and operate it in demo mode free of charge.
Then purchase to convert it to full unlimited operation.

Chopitch Select version 1.1 for your operating system here:
DOWNLOAD (885kB) VST Windows 95/98/2000/XP DOWNLOAD (1110kB) VST Mac OSX DOWNLOAD (1100kB) VST Mac OS9 ( version 1.0 )

Chopan Select version 1.0 for your operating system here:
DOWNLOAD (602kB) VST Windows 95/98/2000/XP DOWNLOAD (1007kB) VST Mac OSX