Here's how you can download the latest version of iTunes free for your Mac.
1. Go to the iTunes download page.
2. Click the Download now button.
Here's a list of system requirements:
Macintosh System Requirements
Mac computer with an Intel Core processor and 512MB of RAM
OS X version 10.6.8 or later
Safari 4.0.3 or later
400MB of available disk space
Broadband Internet connection to use the iTunes Store