From the Toys section:
Amazon has a small special Christmas gift for shoppers today: $2 in free music. Simply head here, click the Button and enter the Code “GIVEMP3S”. $2 will be automatically applied to your account. Use it to buy holiday music or send a small last minute gift to someone? MP3 Gift ideas here.
Promotional offer valid for a limited time only and subject to change. Promotional offer is valid from December 23, 2010 12:00 AM PST through December 26, 2010 11:59 PM PST. You must redeem the credit by December 26, 2010 11:59 PM PST.