You can get a trial on downloads.com.
Then just get the serial from a p2p-program.

Or just get the whole program and crack, key gen, serial or
whatever from a p2p-program, lol.

Oh, wait, you can also get PS legal.
You have $500? Hehe.

Download Emule or other sharing program and download Adobe photoshop cs. Then you will have to active the account or use it for 30 days.

OR

Go to download.com and download the trial