I was notified through an email from EA's Battlefield mailer, but it is also on the Origin game launcher's store section and Origin.com. Both can be found under the "Deals" tab, or just click the link below.
Legal mumbo-jumbo from the bottom of the deals page:
EDIT #1: Looks like some people are having issues getting the sale price, myself included. This is also an issue seen by people at Slick Deals. My advice would be to hold off and try again a little later. I hate to say it but it may be typical EA not having their ducks in a row when doing a promotion. Sorry about that you guys.
EDIT #2: Ok, randomly checked out the store just now and the deals seem live on both the client and website. I tested them myself and you should see the prices be $10 on the shopping cart screen before you even have to input a form of payment. If they aren't then I don't know what to tell you.
Edited by JohnDM, 20 September 2012 - 03:08 PM.