Amazon is currently offering all MP3 Store account holders a $2 credit via a promotional code. All you have to do is type in CLOUDMP3 into the text box on this webpage: http://www.amazon.com/gp/feature.html?ie=UTF8&docId=1000296831. The code is valid up until June 30, 2011. 

So, what are you waiting for? Go ahead and download that song you've been wanting!