Twitter users, if you missed this last week, it's back: Get $1.29 credit (a free song) to use toward any MP3s from Amazon. Says so here. Just follow @Pepsi, then tweet using #PepsiMusicNOW and they'll then send you a Direct Message in your twitter account with a code to use on Amazon for your free music. Thanks, Mercedes.
Then, check out the now over 2,000 free Mp3 downloads you can get from Amazon here.