Sony Online Entertainment has an offer going from September 1st through the 3rd that will double your cash amount on MMO munching funny money. Purchasing SOE’s Station Cash directly through their website OR redeeming a pre-paid Station Cash card during this time will score you twice the card’s face value.
Station Cash is used to power SOE’s empire of free-to-play MMOs such as Everquest, EQ2, DC Universe Online, Free Realms, and the upcoming Planetside 2 and Wizardry Online.
To make the most of this deal, we recommend Walmart's version of the Sony Universal $15 Game Card which comes with an additional $5 worth of Station Cash netting you a cool $40 for $15 deal.
UPDATE: Just confirmed this myself. When redeeming the Walmart $15 card you get 1500 SC (base price) + 500 SC (Walmart card bonus) + 2000 SC (double SC promo) for a total of 4000 SC ($40!).