1) Go to the site above
2) Enter an email address, coupon code priceless and complete the CAPTCHA.
3) Follow link in email to the download site, where you will receive 4 credits.
4) Feel free to go back to Step 1 and use all your throwaway emails for more codes. You can enter all the codes from all the throwaways into one account linked to one email address.
Plenty of songs available from lots of popular artists! All the latest albums too. Daft Punk, Haim, Bruno Mars etc etc, plenty of older artists too. Single songs are 1 credit, if you get a whole album you get a discount on the number of credits. If you need, say, 8 credits for an album, just enter two emails on the link above and apply the two codes you receive.
EDIT: Seems some people are having trouble downloading, while for others it is working just fine. Credits are valid til the end of the year, so if you're having trouble now perhaps try again in a few minutes, or hours :)
Credits expire 31st December 2014
MasterCard music catalogue @ http://music.pricelesssurprises.com
Thanks OP, always wanted to get the latest Justin Bieber album :P
prepares to be flamed