Over at HotCouponWorld, you can download up to 25 FREE songs through Emusic. Click here for details.
Emusic is a subscriber service (so you do need a credit card) which you pay $11.99/month for 30 song dowloads (or 40c per song). Right now they're offering a free trial offer, and should you choose to, you can cancel but the 25 free songs are yours to keep. Not sure how it compares to Itunes or other song download sites, but it's definately worth checking out!