It looks like the Mastercard Marketplace Overwhelming Offer for today will be a $50 Walmart Gift Card for just $25! These offers go very fast, so register now to be prepared. The offer should start at 12:00pm EST!
I know many of you don't use credit cards, but this works with Mastercard debit cards as well. And you only have to provide the first 6 digits of your card to register! Of course you'll need to provide the full card number when/if you make a purchase, but you can check it out risk free.