Discover Card $75 Signup Bonus

It pays to Discover. That is there slogan, and this time they are living up to it with a new promotional code. In fact, Discover Card will pay you a $75 cashback bonus if you apply online using the promo code: DADN. You can also apply by phone, 1-800-210-9022, and referencing this invitation code: DADN. This reward is for new cardmembers only. 
The Fine Print -

Get a $75 Cashback Bonus when you apply by June 18, 2010 and make a total of $500 in purchases with your new card within 3 months of being approved. Promotional reward will be applied within 8 weeks. This promotional reward is in addition to the Cashback Bonus earned on all purchases.

There is no annual fee on this card. It is their popular 5% Cashback Bonus card that offers rewards in categories like travel, gas, groceries, restaurants, etc. However, the categories eligible for the full 5% reward change quarterly and/or monthly. Otherwise, as is standard, all purchases earn an unlimited 1% Cashback Bonus.

Discover also partners with some retailers to increase your Cashback Bonus rewards. Sometimes you can turn your $40 Cashback Bonus into a $50 gift card at participating retailers. In the past, you could even find deals to double your Cashback Bonus.