Downloading MacTar (PPC) 4.2 for Mac from our website was free. The application lies within System Tools, more precisely File Compression.
From the developer:
MacTar reads and writes tar files, a common format used to package files on Unix systems. It can even read and write directly to some SCSI tape drives. MacTar will automatically extract any tar file dropped on it or double-clicked, making it a convenient file-transfer helper.
You may want to check out more software for Mac, such as MActor, which might be related to MacTar (PPC).