Hebcal for UNIX is a free program and is available for download at http://sourceforge.net/projects/hebcal/. This is the same engine that powers the hebcal.com website. The downloadable program has a text (command-line) interface, not a fancy graphical one.
Kaluach is an unrelated program available at http://www.kaluach.com/. The author requests donations, but does not have a set price.