Simply just click the direct links below:
Link 1 ($10) - http://fab.com/?fref=vday&frefl=signupoffer<b=offer
Link 2 ($5) - http://fab.com/?fref=vday5&frefl=signupoffer<b=offer
Allow up to 30 minutes for credits to appear on account.. you'll get them eventually. You'll also see a pop-up when you click the links above so you know you did it right.
$15 Credits expire on Feb 14 2013.
You need an account at Fab.com of course to claim the credits. It's a pretty legit site, I've bought random things from them since the beginning.
An added bonus, if you have an account with them you can do this survey from an e-mail I got for $5 credit (totaling up to $20 with all the credits here, if my math is correct). All you need to do is provide the e-mail adress of your account in the end. Allow up to 24 hours for credit to appear. Link here: https://www.surveymonkey.com/s/fabjanuary
Let me know if it does/doesn't work! Thanks!