Yes, there is a Mac version of RAR:
please download RAR for Mac OS X;
your Mac OS X should be able to extract the tar.gz upon double click without any additional utilities.
Store the extracted files into a new directory within your program folder.

This is a command line version without graphical user interface.
It is controlled by typing commands into terminal. A list of commands and switches can be found in the file rar.txt within the RAR for Mac distribution archive.

If you are not familiar with terminal and you just want to extract some rar files you should have a look onto this short overview at Onsoftware: "Easy to use WinRAR tools for Mac".

There are also some free tools in the Apple App Store: Search for "Unarchiver", "Stuffit Expander" or "Tiny Expander".

If you want to create rar archives you will need RAR for Mac and a license after the trial period is over.
In addition we recommend "BetterZip" from the App Store. It is not free, but it will handle all your archives in Mac style, provides access to extended features like password protection, splitting archives and updating archives without learning all the commands.