Yesterday Zynga told us that the offer for 50% off reward points and the 50% Game Card redemption bonus were good for one day only . They had a change of heart and the offers are good for today as well. This stunt has been pulled many times in the past so most should have predicted it would have happened.
The best bang for your buck is to purchase Game Cards as you will get more reward points. Go here for instructions and a review of the best deals.