Enter the promotional code MP3S4ALL at Amazon and redeem your $2 credit towards music downloads from Amazon MP3.
Promotional offer is valid through 11:59 p.m. PST on June 23, 2012 and subject to change. Limit one promotional credit per customer.
Also, follow @Pepsi on Twitter and tweet using #PepsiMusicNOW. They will direct message you a code for $1.29 off. This credit can only be used towards MP3 purchases.