You can download a trial version. It can be found in the downloads section.
So i guess that would be shareware. No freeware.
It is very powerfull, as it is able to uncompress just about any file. Although, I beleive it only has compression support for RAR and ZIP.
If you want other alternatives of compression, there are tar, gz, ace, bz2, but I am nearly 100% sure those are pretty much only available on the *NIX OSes.
EDIT: added compression information, and forgot to add the edit tag
