Looks like Adobe is giving away the (old) Creative Suite 2 for both Windows and Mac. The CS2 download page contains direct links to all the CS2 products (individual products and the entire Creative Suite 2 installer) AND their license keys.
So if you would like to experiment with Photoshop (legally), but don't want to pay a premium price, this is one way of doing it.
There are some caveats you need to consider:
- The system requirements; The CS2 suite for the Mac doesn't run the Intel CPU, so you need a PowerPC based Mac, OR you need Rosetta. And the latter is no longer available for OSX (Mountain) Lion. I do not know if CS2 will run on Windows Vista, 7 or 8. But you can always run the software in a virtual machine.
- CS2 has a limited Adobe Camera Raw (ACR) converter. Which means that it won't be able to open RAW files from newer camera's. As a workaround you can first convert your RAW files with the Adobe DNG Converter [Windows | Mac], and open those files with Adobe Photoshop CS2.